The evolution of consciousness

105 Scientists struggle to understand how nerve cells create conscious experiences, but we have a model.. 233 How can we exploit our knowledge of the human brain in order to further impr

The

Evolution of

ConsciousnessImplications for Mental Health and Quality of Life

The Evolution of Consciousness

Division of Mental and Physical Health

Norwegian Institute of Public Health

Oslo

Norway

This book is a translated and enhanced edition in English language:

The Evolution of Consciousness: Implications for Mental Health and Quality of Life

by Bjørn Grinde

The book was originally published in Norwegian language:

Bevissthet Forstå hjernen og få et bedre liv by Bjørn Grinde, © 2014 Spartacus forlag AllRights Reserved

This translation has been published with thefinancial support of NORLA

ISBN 978-3-319-43683-8 ISBN 978-3-319-43685-2 (eBook)

DOI 10.1007/978-3-319-43685-2

Library of Congress Control Number: 2016947203

© Springer International Publishing Switzerland 2016

This work is subject to copyright All rights are reserved by the Publisher, whether the whole or part

of the material is concerned, speci fically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission

or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed.

The use of general descriptive names, registered names, trademarks, service marks, etc in this publication does not imply, even in the absence of a speci fic statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made.

Photos and illustrations are from the author unless otherwise stated.

Printed on acid-free paper

This Springer imprint is published by Springer Nature

The registered company is Springer International Publishing AG Switzerland

I would like to thank my Norwegian publisher, Spartacus Forlag, for allowing me tofreely pursue a text in English related to a book I published with them I also wish

to thank Hendrikje Tuerlings in Springer for believing in the project Some peopledeserve special thanks for taking time to do a critical reading of various versions

of the text They include Dagfinn Føllesdal, Lowan Stewart, Michel Cabanac, and

my son Steinar Grinde

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1 A Conscious Life 1

Why consciousness is a topic that should occupy the mind of conscious people Key concepts are introduced and the phenomenon briefly described Conscious and Unconscious Processes 3

Should We Aim for Reason or Happiness? 10

2 The Brain—Your Personal Necktop Computer 19

The chapter provides an introduction for those who are unfamiliar with the inside of their head Ifind it helpful to compare brains with computers The Anatomy of the Most Complex Object 19

Neuron Style Talking 23

The Concept of Brain Modules 29

Brain Versus Computer 36

3 The Evolution of Nervous Systems 43

The process of evolution gives us the principles required to make sense of life on Earth The development of nerve cells was one of the biggest breakthroughs; yet, in the beginning nothing suggested where this innovation would lead Why Nervous Systems? 44

Further Improvements 48

On Bees and Octopuses 53

What Is Intelligent Behaviour? 59

4 Conscious Brains 63

Thefirst signs of consciousness probably appeared some 300 million years ago It was a risky venture, so why did evolution choose this path? Surprisingly, refinements eventually gave rise to a species with the capacity to answer the question A Common Currency 63

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Hence Consciousness 68

When Did It All Start? 75

Signs of Consciousness in Animals 79

When Is It Needed? 87

Has It Been a Success? 90

How We Became What We Are 92

The Human Case 96

I Think, Therefore I Am? 100

5 The Neurobiological Correlate 105

Scientists struggle to understand how nerve cells create conscious experiences, but we have a model The model suggests which parts of the brain are involved and what goes on there Cortex and Thalamus 106

Integrated Information 117

What We Can Do Without 119

We Learn When Something Goes Wrong 126

The Bigger the Better? 132

The Hardest Problem 134

6 States and Disorders of Consciousness 139

There are many facets to a conscious life Besides the gradual transition from full attention to sleep and anaesthesia, several factors affect what sort of experiences the brain serves you Sleep 140

Anaesthesia 146

Life History 148

Maladies Affecting the Mind 151

Wilfully Altered States 156

7 Quality of Life 159

Understanding consciousness offers valuable insight into what happiness is about The text consequently provides an approach for improving life Hedonia and Eudaimonia 159

The Mood Modules 162

On or Off 172

Mental Disorders 176

Darwinian Happiness 177

8 Environmental Concerns 181

The brain is designed to develop in interaction with external stimuli, which means we are shaped by the environment in which we live The question is therefore how to provide conditions that have a positive effect on the human mind? Childhood and Life Situation 182

The Damage Due to Discords 188

The Achilles Heel 193

9 Mental Exercise 199

In addition to creating a suitable environment, it is possible to exercise the brain to the effect of tuning up pleasures and turning off pains This requires a proper training routine Use Your Head 199

The Psychological Challenge 204

Meditative Techniques 212

Technical Tools 217

Habits—For Good and Bad 223

A Model of the Mind 230

10 In the Future 233

How can we exploit our knowledge of the human brain in order to further improve quality of life? The Main Challenge 233

Next Generation Gym 238

A Final Word 245

Bjørn Grinde received his education in naturalsciences, psychology, and anthropology from theUniversity of Oslo, ending with a Dr Scient.(1981) and a Dr Philos (1984) in biology He ispresently the chief scientist at the Division of Mentaland Physical Health, Norwegian Institute of PublicHealth Previously, he has served as a scientist andprofessor at leading universities in Norway, the USA,and Japan A primary focus of his research has been tounderstand the process of evolution, particularly how

it has formed the human brain and our capacity toenjoy life He has written several books, includingDarwinian Happiness (The Darwin Press, 2002; 2nd Edition, 2012); God—AScientific Update (The Darwin Press, 2011); The Biology of Happiness (SpringerVerlag, 2012); and Improving the Human Zoo (The Darwin Press, 2015) Togetherwith Professor David Sloan Wilson at Binghamton University, NY, he is engaged

in research aimed at practical ways to improve people’s quality of life

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With this book, I shall present a model for how the evolutionary process led toconsciousness, as well as what is known about how the brain accomplishes this feat.Besides offering a description of what human life is about, the text is meant to helppeople deal with their brains That is, you can sway the brain in the direction ofoffering more positive experiences and thereby improve your quality of life.Chapter1 presents the human brain and discusses why we ought to study thisproduct of evolution Chapter2describes the anatomy of the brain and how nervecells (or neurons) operate It is useful to have at least some knowledge of this organand to master the relevant terminology; but if you shouldfind the chapter heavyreading, it is possible to grasp the more important aspects of later chapters evenwith limited knowledge of the brain In Chapter3, I describe evolutionary history—more specifically, the history of the nervous system It started some 600 millionyears ago and led to some fantastic products, the most interesting being brains withthe capacity for awareness As suggested in Chapter 4, this innovation occurredonly once on Earth The human version of a nervous system is arguably the mostadvanced product ever created by the process of evolution.

I occasionally use expressions such as“evolution desires” or “the genes wantyou to.” I should warn that these are just convenient shorthand for saying somethingabout what sort of tendencies are embedded in the genes—I do not suggest that theprocess of evolution, or the genes, has any willpower

After trying to describe a scenario for why evolution ended up with a conscioushuman brain, I discuss how this piece of tissue generates awareness (Chapter5)

“How the water of the brain is turned into the wine of consciousness.” Identifyingthe neurobiological correlate of consciousness implies indicating which parts of thebrain are involved and what sort of activity is required

In the following Chapter6, I discuss the various forms of experiences the brain

is capable of offering Consciousness is not one particular condition, but anadventure that takes many forms Besides, the brain regularly decides to turn it, orrather you, off

The insight you will hopefully have acquired by studying thesefirst six chaptersprovides the basis for taking steps to improve life—to make it happier In Chapter7,

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I present a model for what happiness is about, in Chapter8, I consider how we mayimprove conditions of living in order to enhance quality of life, and in Chapter9,

I discuss various strategies aimed at training the brain in the direction of providingmore desirable feelings Readers primarily interested in these practical aspects mayfind the former chapters somewhat lengthy My main ambition in life is to under-stand what consciousness is about, and I admittedly delve deeper into the subjectthan what is really required It means that if you dofind parts of the text difficult, orwish to skip sections, that should not discourage you from reading the three morepractical-oriented chapters Similar advice could be given to those primarily inter-ested in the theoretical part of the book Thefirst six chapters, which describe whatconsciousness is about, are independent of the last part

In the end, I look to the future, trying to picture what lies ahead for human brainsand their owners (Chapter10)

It seems like most people dislike instruction manuals, they prefer to“plug andplay.” This may work well with the typical computer program, but what if the taskahead is to operate a human brain? I believe not only that the brain is more complexthan a PC or a smartphone, but it is—at least in some aspects—less intuitive tohandle

You were not handed an instruction manual at birth The present text is meant tocompensate for that Computer games are likely to be more fun if you take thetrouble of learning the rules, and I believe the advantages of taking the trouble toread the manual are considerably greater when dealing with the mind

There are many ways to describe reality—including the human brain Sciencehas developed several independent traditions, each setting up models and para-digms in an effort to reveal the workings of anything from the mind to the universe

As to the former, the social sciences and philosophy present a rather differentviewpoint than the natural sciences There is no obvious answer as to which model

is right or wrong—even if you might think so when listening to discussionsbetween professionals rooted in various disciplines A major problem is that eachparadigm has a particular set of technical terms I write as a biologist I stronglybelieve that the description of consciousness offered by this discipline has con-siderable merit, but readers with other professional backgrounds may need to make

an effort in order not to misinterpret the conceptual apparatus I use I shall try toexplain key terms as I proceed

Scientific references are provided in footnotes Their number has been limited inorder to retain space for the main text, and the focus has been on recent reviewsrather than original empirical work

going on behind the walls There are windows, but some have the curtains drawn, in others you only see re flections The question is how to gain relevant insight? (The Schloss Wernigerode, Germany)

A Conscious Life

Abstract The first chapter explains why consciousness—in a way—is all you got.Without the capacity to experience life, there is really nothing in it for you This iswhy you ought to understand this feature of the human brain In other words, youare just an“app” that the unconscious part of the brain turns on in the morning andoff at night Moreover, the unconscious brain is partly responsible for directing your

“film of life”, based on instructions laid down in the genes The chapter introduces

an evolutionary perspective that helps us understand the human mind, as well askey concepts related to the study of consciousness

Is it possible to live without experiencing anything? And would this be a life worthliving? For the majority of Earth’s organisms, the answer is presumably “yes” Treeslack the device required to have any form of awareness—a nervous system—yetthey stretch toward the sky and appear to thrive In one way, they are lucky Theyare not at all bothered by this deficit; because without a nervous system, and acapacity for emotions, it is not possible to be bothered by anything Still, I do notenvy the trees I choose to consider the opportunity to take part in the life of mybody as a bonus Feelings are—after all—often quite pleasant; and by applyingcurrent scientific knowledge, it is possible to make life even better

Consciousness is the gift of nature that turns you into a participant We take it forgranted, because it is so easy to employ, and so obviously required for anything tomatter at all But it is indeed a strange feature; in one way it is all that life is about,but at the same time it is something vague and indescribable We can isolate anddissect a nerve cell, but trying to grasp what an experience—a moment in the film oflife—is actually about, can be compared to a Stone Age person trying to figure outwhat air is The air is there, you breathe in, the birds beat their wings against it, butyou see nothing and sense nothing Science has solved this mystery We can explainpretty much anything worth asking about the Earth’s atmosphere; but is it at allpossible to comprehend our ability to experience life?

The philosopher John Locke was right: my consciousness—it is me.1Without it,there is nothing I can bear the fact that my mind at times is fatigued or distorted; in

1 From Locke ’s most famous work: An Essay Concerning Human Understanding (1689).

© Springer International Publishing Switzerland 2016

B Grinde, The Evolution of Consciousness,

DOI 10.1007/978-3-319-43685-2_1

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fact, for shorter periods I survive without consciousness At night, the unconsciouspart of my brain takes charge Under narcosis doctors ensure that there is enoughactivity left in the nervous system to keep my body going; that is, to make sure myheart pumps and my lungs breathe Actually, the body can survive without a brain,

or at least without a mind, if it happens to be in a suitable hospital bed equippedwith the necessary connections But then that body no longer carries me

In the 19th century, scientists struggled to explain what life is, and how matter—

in the form of simple atoms—gives rise to anything capable of moving or growing.Today we have comprehensive answers to these questions In another hundredyears we may have reached equally far as to explaining how the same matter, thebuilding blocks of our bodies, give rise to cognition Your body contains some 1028atoms that act according to the laws of physics They form the molecules that againbuild the cells Some of these cells, the neurons, work together to generate what youexperience I believe there is no reason to postulate anything supernatural; we just

do not know the details as to how this happens

One thing we can be certain about is that consciousness exists Philosophershave argued that this is the only thing we can be sure of! Without some form ofcognition, we would be unable to ponder the subject of existence; our capacity toobserve life is based on this property of the brain It is theoretically possible tocreate a virtual world where everything you experience is based on exposing thebrain to artificial stimuli—as in the virtual reality of science fiction The capacity toactually experience these stimuli would then be the only true reality left

Is there anything more exiting in the Universe than trying tofind out what this isall about? And is there any corner of the Universe that is more important to studythan the clump of matter hidden behind your eyes? I have been drawn to the topic

of the human brain, and particularly our capacity for awareness, for as long as I canremember It led me to study biology and social sciences; and then on to pursue acareer as an evolutionary biologist—because I believed this approach providesimportant insight Evolution is the framework that allows you to put all the pieces

of the puzzle into their right spot It opens a window to the human mind.Unfortunately, the human mind is a double-edged sword in that it offers bothpleasures and pains (I use “pain” in the broadest sense, all sorts of unpleasantexperiences are included.) The art of living is about how to make the most of thissituation You ought to learn to control the sword, that is, to act as a director for theorchestra of neurons The good news is that this is not an impossible challenge!You can learn to exploit your brain by utilizing the measure of free will evolutionhas bestowed upon us You can learn to influence your emotional life in a positivedirection The bad news is that you are up against a formidable challenge Evolutiondid not, for very good reasons, leave your emotional life, or for that matter yourheartbeat, at the jeopardy of your whims What if you decided to simply stop theheart, or to turn off the pain of burningflames instead of escaping from a house onfire? You would avoid agony, but your genes would certainly “cry” The brain isdesigned for sustaining life—not stopping it Suicide is meant to be difficult

To master the task of orchestrating your symphony of conscious experiences, it

is important to know something about the players in the ensemble The mind is asinvisible as air, and considerably more complex and mysterious; but thanks toscience we can sketch out some of its properties

In the brain, information from various sources joins to produce a uni fied experience of the world (From Plitvi ča, Croatia)

Conscious and Unconscious Processes

Do you know what you see?

The eyes are there to provide facts about the environment, but they pick up a lotmore information than you realize The signals leave the eye via the optic nerve andend up in the primary visual centre in the back of the brain From there onlyselected fragments are passed on to consciousness—that is, to you The way youperceive reality is, in other words, a matter of which sensory information the brainchooses to serve Of all the light rays hitting the retina, only a certain fraction goesall the way to form a visual impression Moreover, the unconscious brain not onlyfilters the information coming in, it processes and interprets it in a way that meansyour impression of what is going on can be quite distorted Most of us have, forexample, been fooled by magicians to“see” things we never actually saw

For me the term unconscious covers the processes in the brain that you areunaware of These processes are active whether you are awake, asleep, or anes-thetized Some of them deliver content to your conscious experiences, while otherstake care of functions you do not need to know about such as the heartbeat There isconsiderable communication going on between the unconscious and consciousbrain You are therefore theoretically able to influence parts, perhaps most, of what

is going on unconsciously Sometimes you experience that ideas or informationcome to you from“out of nowhere” For example, at first you fail to recall the name

of a person, but you wish to know The deeper part of the brain takes the message,searches the memoryfiles, and then, perhaps ten minutes later, the name pops up inyour mind

Donald D Hoffman, a cognitive scientist at the University of California, pares the interface between the conscious and the unconscious with a computerscreen.2 There you find icons that can be used to activate various programs orfunctions in the computer By pushing these icons, you have a measure of control,but you have no idea as to how the various programs actually execute tasks Andsince you do not know what goes on behind the screen, or in the unconscious brain,neither are you in a position to verify whether what you perceive has anything to dowith reality

com-I use the term subconscious for the frontiers between the conscious and theunconscious That is, the two latter terms cover everything that goes on in the brain,but the borderline between them is somewhat blurry This blurriness gives rise tothe notion of intuition Sometimes ideas, or advice as to actions, are brought outfrom the unconscious part of the brain in a way that leaves you with the feeling ofnot knowing the rationale behind

Actually there are two common ways to use the term consciousness One cerns a state of mind or level of arousal, for instance, fully awake as opposed todrowsiness or deep sleep The other concerns the particular content of our expe-riences, as in the sentence, “I am conscious of the smell of this orange” I shallprimarily use the former meaning

con-The word mind roughly corresponds to whatever takes place in your consciousbrain

The somewhat related term percept is often used to describe the content of ourexperiences It refers to the part of the conscious experience brought on by thesenses It can mean either an element of a larger picture, or the entire scope of whatthe senses offer at a given moment The former could be the green colour of anapple, or certain notes from a Beethoven symphony; the latter reflects the completevisualfield with the addition of whatever sounds or smells you are aware of at thatmoment I like to consider“percept” as a more narrow concept than “mind”, in thatthe former is restricted to what the senses have to offer

2 I recommend his TED talk: https://www.ted.com/talks/donald_hoffman_do_we_see_reality_as_ it_is?language=en

You are equipped with a variety of senses Besides your eyes, you have systemsfor detecting sound, smell, taste and touch Your perception of reality depends onwhat these systems are able to capture, and how the unconscious mind digests theinformation But sensual information is only one out of several sources that delivercontent to your conscious experiences Other parts of the brain provide completelydifferent types of contributions; your“inner life” includes thoughts, daydreams andmemories Last, but far from least, there are nerve circuits that add a particularquality—they attach feelings Feelings are either positive or negative, you like ordislike whatever it is you are up to The good or bad aspect works like a dressingthat permeates the salad of other input, whether this derives from your senses oryour imagination It turns your conscious mind in the direction of pleasure or pain,you are happy or discontent.

To summarize, conscious experiences are based on three types of input: (1) formation from the senses; (2) internally generated content such as thoughts andmemories; and (3) feelings You are the sum of all this

in-Your consciousness is unique Nobody else experiences things the way you do.Actually, there is one possible exception to this rule: the twins Tatiana and Kristashare at least parts of their lives, in the true sense of sharing! I shall return to thesetwo girls later in the book because they offer a unique opportunity to understandwhat consciousness is about

It is easy to accept that the sense organs have their limitations We hear, forexample, only sounds within a certain frequency range; light is a form of electro-magnetic radiation, but the eyes capture no more than a small portion of the totalspectrum of waves Many insects have eyes that perceive UV radiation, but a worldwith only UV would mean darkness for us In addition to these limitations, there arefilters that all information has to pass through in order to reach consciousness, andthere are manipulations of content All in all it is a bit like how the Chinesegovernment handles the Internet In fact, both the Chinese authorities and theunconscious brain perform this task in strange and mysterious ways.3

I believe I understand the motivation of the Chinese, but why does the brain notoffer you an uncensored and exact version of reality? Is this distortion and cen-sorship really in your interest?

A certain type of mental disorder points towards a possible answer Peoplediagnosed with autism struggle to function socially, but some have an almostsupernatural ability to capture and remember every possible detail of what they see

We call them savants One theory says that autists have an error in the brain systemsdesigned to process information Consciousness becomes so overwhelmed by inputthat it fails in other tasks such as interpreting and responding appropriately to

3 As to the Chinese, see Hvistendahl M Study exposes Chinese censors ’ deepest fears Science 345 (2014) 859 –860; as to the brain, continue reading.

signals from people.4Whether this theory is correct or not, we know that awarenesshas limited capacity; so you ought to be pleased that the rest of the brain steps in byadministrating and interpreting theflood of information.

Another relevant point is that the genes, roughly speaking,“wish you well” Theunconscious processing of reality quite often improves your quality of life Forexample, if you embarrass yourself, the brainfirst looks for someone else to blame;and if you fail to think of an external cause, the unconscious makes sure you forgetthe whole episode The psychologists refer to these two phenomena as, respec-tively, displacement and selective memory In many situations it makes good sense.The processes that preside over your experiences make life a bit more comfortablethan what you really“deserve”, presumably because the genes are better off if you

do not despair

On the other hand, the way your brain is constructed may also smash your lastvestiges of happiness One of the main functions of emotions is to make sure you donot hurt yourself; you feel physical pain because the genes prefer to be enclosed by

an intact body Consequently, you avoid hitting yourfingers with a hammer, and youget scared standing on the edge of a cliff—it is the interest of the genes for you to becareful They also ensure that you remember bad incidents by associating them withdiscomfort, in that way you learn to act cautiously and avoid danger later in life Theproblem is that we are adapted to live in what may be referred to as the Stone Age;current environment creates quandaries because it is different from what our genesare tuned to In the Stone Age, the system handling potentially unpleasant sensationspresumably workedfine, but today people end up in (genetically speaking) unex-pected situations The quarrel with a neighbour, for example, remains unresolvedbecause you have the option of avoiding each other; in the Stone Age people needed

to cooperate with their tribal comrades Soldiersfind themselves in the firing lineunder continuous threat of bullets and bombs, while the danger of meeting a lion willresolve rapidly—in one way or another The mental impact formed by the experi-ences of war can pester a person for life, as they do in people diagnosed withpost-traumatic stress disorder In these people bad feelings get the upper hand in thebrain The soldier knows very well that it is best to avoid bullets and bombs, thus thelong-term discomfort associated with the stress disorder seems superfluous.The unconscious is“well-intentioned” when it comes to handling consciousness(at least in the sense of helping your genes), but as indicated above it is notdesigned to always give priority to your quality of life Fortunately, your dose offree will offers an opportunity to take matters in your own hands Awareness givesyou a bit of leeway You can to some extent control your mind by choosing what tofocus on and what sort of sensual information to obtain The better you understandthe workings of the brain, the more options you have

4 Markram H, Rinaldi T, Markram K The intense world syndrome —an alternative hypothesis for autism Frontiers in Neuroscience 1 (2007) 77 –96.

That said the unconscious brain is certainly not lacking when it comes topushing you in various directions Consciousness did, after all, evolve to help theunconscious brain—not vice versa You are, for better and worse, not the sovereignruler of either body or brain Right now you are focusing on this text If you arereally immersed in the words, you do not see the cat sneaking in from the left; but ifthe cat suddenly jumps at you, the unconscious makes sure you jump as well Thefocus is suddenly on the cat The brain does what it can to make you pay attention

to whatever is potentially important for your genes

The type of experiences you are guided toward is a matter of what proved usefulfor the genes during our evolutionary history As they say in the secret services,

“information is given on a need-to-know basis” You, that is your conscious life, are

a compromise between the push of the unconscious and your capacity forself-determined choices Sometimes it feels more like a continuous struggle Thus

no matter how much free will you may think you have, it is useful to note that in thedepths of your brain sits a“zombie-like creature” that is actively engaged in con-trolling your life

The process of evolution standsfirmly behind all this It has shaped your genes,which in turn participate in shaping your brain, which is what creates you The brain,and the rest of the body, is a product of the interaction between genes and environ-ment You can choose to define yourself as what you experience—thoughts, feelingsand sensations; in short, your consciousness—or you can include the rest of the body

in the concept of self Perhaps most people choose the latter They look at everythingfrom toenails to hair locks as part of themselves, but for all practical purposes, it is theexperiences that matter If you kick a rock, the pain emanates from the toes, but it isthe brain’s ability to create conscious feelings that causes the suffering

Feelings is a key concept in this text The three terms—feeling, emotion, andsensation—are overlapping All three may imply something good or bad (pleasure

or pain) in combination with some sort of“flavour”; where the flavour can be, forexample, love, friendship, fear, the vision of a rose, or the taste of coffee I like touse feeling as the all-encompassing term (although at times I do focus on thepleasure or pain when using this word) The word emotion focuses on theflavour.The flavour is meant to guide your behaviour or teach you a lesson (e.g., get toknow that boy, or stay away from the cliff) Sensations are experiences based oninput from the various senses They typically engage less cognitive processes thanemotions, but tend to involve a positive or negative experience We sense the smell

of a rose and may, for various reasons, appreciate that sensation The term sensationalso covers information coming from our internal “senses”, such as those moni-toring bodilyfluids (thirst) or nutrients (hunger)

Sensations provide guidelines for behaviour You see an apple and want to pick

it up because you suddenly feel a bit hungry Thus there is no distinct line betweensensations and emotions If you spot a girl and want to go to her, we refer to it as

“love”, which is considered an emotion Biologically speaking both the apple and

the girl serve your genes, they help you survive and procreate, but cultural ventions have installed different terms for various types of emotional instigations.Emotional states are typically meant to be communicated to others, which means

con-we can read them in facial and bodily language We display sadness and anger,while sensations such as thirst or hunger are not visible (unless they move on to alevel that causes the brain to activate despair)

Particularly in the case of sensations, the “good or bad part” is not alwayspresent—or at least not obvious For example, if you look at a building, you mayenjoy some aesthetic quality, or you mayfind the vision trivial Similarly, the touch

of another person’s hand can be a reasonably neutral event, or it can feel like apleasant or unpleasant tickle In fact, the simple awareness of who is performing thetouch—yourself, your companion, or an adversary—grossly affects the way youexperience the contact You cannot tickle yourself, and self-caress simply is not thesame as caress supplied by another person

How much freedom is needed to have free will?

Our genes offer us a luxury version of a brain with amazing features likeconsciousness, intelligence and language as standard apps This package alsoincludes a solid measure of free will You cannotfly like a bird, or follow ascent like a dog, but within the limitations of our species, you—that is yourconsciousness—certainly have something to say The ability to make choices,

as to both physical actions and what the mind is up to, is part of the brain’sdesign As with other mammals, the choices made are admittedly influenced byurges and emotions initiated in the depths of the unconscious, but you have a

definite capacity to override many of these—if you take time to stop and think

So do we have such thing as a free will?

The way I see it, we have freedom enough to choose whether the answershould be “yes” or “no” The response is, after all, primarily a semanticchoice: How free should the will be before it becomes appropriate to answeryes? We can control reasonably well how we behave, including whether wetake the advice offered by emotional instigations, but it is more difficult(albeit not impossible) to control the emotions that pop up You can choosenot to eat, but it is hard to decide not to be hungry Your free will is limited tothe realms of consciousness; in the unconscious part of the brain, there is littlefreedom You cannot decide to stop the heart, as processes outside ofawareness regulate the heart muscles; obviously the genes would not“cher-ish” the idea of such an important function being open to your whims.Most people believe they are in charge They like the idea of being king oftheir own mind and body Unfortunately, or perhaps fortunately, they rarelyrealize it when feelings (and unconscious triggers) seize command That sort

of phenomenon is easier to detect in others You take note of the more or less

irrational, emotional actions of your friends, but prefer to see your ownbeliefs and behaviour as highly rational.

In other words, people tend to listen to the hints inherent in our geneticconstitution and delivered by the unconscious brain You may still choose toclaim a free will, but the level of freedom is, perhaps, slightly lower than youthink

A recent argument against a free will is that we can detect brain activitythat statistically correlates with a particular decision before a person reports tohave made that decision.5However, as will be discussed in Chapter 5, thisobservation does not rule out that you have a say

The unconscious part of the brain not only affects what you experience, but alsowhen you have the opportunity to participate in life At night, it turns off the switch,but next morning you are called upon again

We do not know why we sleep away perhaps a third of our lives, but one likelyexplanation is that it helps save energy Humans are diurnal animals—unlike anumber of other mammals adapted to be active at night For our ancestors, therewas consequently not much use in staying up after sunset Furthermore, both bodyand brain need rest to function optimally One theory is that the unconscious needs

to escape the hustle and bustle of the conscious you in order to“clean up the nervepaths”, a clean-up that includes updating the memory archive.6Anyway, consciouscontrol is not needed when there are no decisions to be made, and may as well beturned off for the same reason you turn off the lights in the living room when you go

to bed Bodily functions are cared for anyway Nevertheless, if in the middle of thenight the unconscious recognizes danger, perhaps a sudden sound, is makes sureyou enter the arena

The brain is equipped with an innate tendency to steer you and your experiencestoward what is (or was in our Stone Age past) essential for survival Unfortunatelythis leads to a few problems For one, what was important for our distant ancestors

is not necessarily where the shoe pinches today; and two, the interests of the genes

do not always coincide with what is best for you You are not designed first andforemost to be happy, but rather to bring on the genes Perhaps the main reason forunderstanding how the brain works is to obtain a slight leverage when combatingthe unconscious“zombies” that guard the mind

5 Soon CS, Brass M, Heinze HJ, Haynes JD Unconscious determinants of free decisions in the human brain Nature Neuroscience 11 (2008) 543 –545.

6 Xie L et al Sleep drives metabolite clearance from the adult brain Science 342 (2013) 373 –377.

Consciousness implies a stream of experiences that can be compared to a film or, for the sake of illustration, a waterfall The unconscious helps you limit the amount of water so you will not drown in information (From Plitvi ča, Croatia)

Should We Aim for Reason or Happiness?

The brain is not constructed with the same logic and elegance as a computer.Superficially, the evolutionary process seems quite rational; but upon taking acloser look at its products, it becomes clear that the process has its limitations Onthe other hand, I believe most biologists will agree that the human brain is the mostfantastic product ever to appear on this planet The point is that even so, ournervous system is far from an elegantly composed construct Rather than awell-designed estate, it has the appearance of an old shack It can be compared to anold house that has been repaired, expanded, and adapted to new inhabitants thou-sands of times The roof may keep the water out, but the room-plan and plumbingare far from ideal Why, for example, did the visual centre end up at the back of thebrain when the eyes are up front? The solution can be compared to the oil com-panies operating in the North Sea deciding to bring the gas ashore in Africa ratherthan in Norway The process of evolution probably could not hold down a job with

an oil company; its fantastic achievements are here because, unlike the techniciansoperating offshore, it has been at the task for close to four billion years Moreover,

perhaps somewhat like the oil companies, elegance and optimality is not important

as long as you are ahead of competitors

Part of the limitations inherent in the evolutionary process has to do with the way

it moves forward It is not possible to tear down an existing solution, or“house”,and make a fresh start by erecting a new one based on more recent technology andneeds Instead it has to advance by making small steps of“restorations”, one at atime, in the form of random mutations in the genes Besides, the nervous systemwas never designed to be perfect, or logical; all that matters for evolution is to retain

a capacity for survival and procreation Thus human thinking and behaviour are notnecessarily rational (even when measured according to what benefits the genes).Our capacity for logic is largely a hard-earned feature requiring a concerted effort.More often, it is an illusion For example, a range of studies have shown that whennew information conflicts with existing belief, we struggle to keep former beliefsintact rather than to revise them Most people would agree that everybody else attimes are irrational, the hard part is seeing the same tendency in oneself

On the other hand, if life quality is what you are looking for, and not just anopportunity to win the world chess championship, there is no obvious reasonalways to strive for rationality In fact, I believe it can be rather irrational to opt forbeing rational! Picture yourself as ninety years old and close to dying Is this thetime for conjuring images of mouldering corpses—or rather for focusing on a life tocome in a suitable heaven? The choice is yours, but I believe the level of happinessmay be best served by going for a vision of some sort of existence after death Thepoint being that there are situations in life where logic may turn happiness tosorrow Obviously there are also situations where rationality ought to prevail.For good reasons, evolution equipped the brain with a sophisticated“cosmeticsdepartment” The brain grooms the information sent towards conscious perception.The cosmetic feature helps you suppress things you are best served by forgetting,and believe in things because the belief serves you well, not because it is in any wayaccurate In addition, the unconscious brain initiates an extra “colouring” ofexperiences in the form of feelings Sometimes they are good, at other times dis-agreeable; sometimes highly distinct, such as the fear evoked by a sudden, sharpnoise in the middle of the night; at other times they are just a vague influence youhardly notice But they do not add accuracy to your vision of the world Actually,even feelings you do not consciously recognize has the capacity to impact on yourchoice of behaviour and most likely on your mood as well.7

It is important to remember that your conception of reality, and thereby yourchoices, is based on experiences that have been through processing in the uncon-scious depths of your brain There is nothing wrong with this situation—it is theway evolution has shaped us The point is that in order to understand the result(your conscious awareness), and how to impact on it, you ought to recognize theactivity that shapes it This includes an appreciation of the processes taking place in

7 Tamietto M, de Gelder B Neural bases of the non-conscious perception of emotional signals Nature Reviews Neuroscience 11 (2010) 697 –709.

the mysterious, unconscious part of the brain We tend to believe that consciousness

is all there is, simply because it is all we got In reality your life reflects only thesurface of an ocean of brain activity

Our experiences are an amalgam of a complex mixture of components You donot necessarily conceive the individual factors because they tend to be integratedinto a unified whole Seeing the face, hearing the voice, and smelling a person youlove are all mixed in with the emotions you have for this individual The varioussenses, such as sights and sounds, supply their contributions; your personalthoughts are often incorporated; while feelings constitute the third major type ofelement represented

The purpose of feelings is to guide behaviour in particular directions – theirconsequence is for you to either enjoy life or have a hard time

The happiest man in the world?

Matthieu Ricard has about the same background as me; he is educated inmolecular biology Some years ago he made newspaper headlines around theglobe as the world’s happiest man! How did he achieve that?

Ricard got his Ph.D in the lab of a Nobel Prize winner and was considered

a particularly promising biologist However, at an early stage in his career,Ricard left the circus of science for a life as a Buddhist monk in Nepal, where

he focused his attention on meditation

Richard Davidson is a highly acclaimed brain scientist By means ofelectrodes attached to the skull, as well as various forms of brain scans,Davidson measures activity in discrete brain regions.8The regions associatedwith positive emotions are among his main interests Buddhists have a longtradition of using meditative techniques for the purpose of creating a goodlife; which is why Davidson chose to enrol some monks—including Ricard—

in his experiments Ricard came out with the highest score when measuringactivity in parts of the brain assumed to generate positive feelings—thus thetitle in happiness

Neither Davidson nor Ricard claim that the award is deserved The surements were performed on a small group of people, and the particular type

mea-of activity tested is, at best, a vague indication mea-of the brain’s capacity to dishout good feelings On the other hand, we are talking about serious science, andthere is every reason to believe that the training Buddhist monks go throughactually helps Happiness is something you can reach for! In Chapter 9, Idiscuss how to conduct proper training

Perhaps one day happiness will be an Olympic event It is arguably a morehealthy ambition than trying to become the world’s fastest runner, at the veryleast it is more likely to improve your quality of life In the meantime, you

8 Lutz A et al Long-term meditators self-induce high-amplitude gamma synchrony during mental practice Proceedings of the National Academy of Science USA 101 (2004) 16369 –16373.

may want to buy Ricard’s book, Happiness: A Guide to Developing Life’sMost Important Skill What he earns goes to humanitarian causes, which isactually how he found happiness.9

The sum of what goes on in the mind is like afilm You may think of it as the film

of life—a mixture of fiction and documentary; an assortment of feelings, thoughts,and information from sense organs that roll by on the canvass of consciousness It is

a singlefilm because you can only have one experience at a time; but then you arenot just a spectator, you also have a key role The scenes appear to move in acontinuous fashion, but in reality they jump from one image to another Like in arealfilm, the frequency is high enough for you not to notice the shifts; but as youmay have experienced in old-fashioned cinemas, the pictures sometimes“hang” It

is a rare condition, but the neurologist Oliver Sacks has described patients sufferingfrom what he calls stroboscopic vision—their visual impressions do not flowcontinuously.10

In a way, thefilm of life is all we have—all that matters anyhow—yet it is aperformance without an actual substrate At best, fragments are stored for you toretrieve as memory later in life; but for all practical purposes, thefilm is only shownonce—it is your life The good news is that you do participate in directing the show

Of course, afilmmaker is never omnipotent when it comes to the product, but youare in a position to influence what sort of film it will be: drama, comedy or tragedy.Admittedly, the end tends to be tragedy, as the lead character inevitably dies in thefinal act Thus the best you can achieve is to make sure that the remaining show isworth seeing In order to do so, you need to know what instruments and options are

at your disposal as a“director”

The show takes place in the brain Poets may put their bets on the heart, but as abiologist, I feel certain that the heart alone has roughly the same potential forexperiences as a potato True, signals from the rest of the body affect the head, but it

is up there everything is put together into complex scenes For all practical poses, the“camera” has its correlate somewhere in our central nervous system So

pur-to understand our ability pur-to participate in life, it is necessary pur-to study the brain.Science has relatively detailed knowledge about the functioning of nerve cellsand how they communicate, but unfortunately it is far more difficult to understandhow this activity gives rise to consciousness and cognition Unlike neurons,awareness is not something tangible that scientists can grasp and explore usingtraditional methods Religious people like to think of it as a property detached fromthe mundane, biochemical processes of life Some go so far as to imagine a feature

of the universe—a sort of unknown element uniting all there is—something we

9 In his book (2007, Atlantic) Ricard points to the importance of meditating on compassion and thereby improve ones capacity for empathy.

10 Sacks O Hallucinations (2012, Vintage Books).

humans have the capacity to tune into, but dating back to the primordial soup Theytalk about panpsychism Consciousness exists in everything and everywhere Or,perhaps, as the philosopher Descartes would have it, life is composed of body andsoul, where the soul is independent of body and consequently liberated from whatgoes on in the brain.11The idea is nice in that it offers hope for the spirit to live onafter your body rots, but it is frustratingly difficult to substantiate.

Strange and mysterious phenomena leave the door open for fanciful tions In 1667 the German physician Johann Becher suggested thatflames consist of

explana-an element he called phlogiston.12 All flammable materials contain this element,which is released when they are ignited The theory has been abandoned I believethe idea that consciousness is related to somethingfloating in the universe, freedfrom the individual’s bodily existence, will suffer the same fate In this respect, I am

a reductionist: thefilm that constitutes your life has a physical correlate in terms ofactivity in the brain—activity that we slowly but surely are beginning tounderstand

I may be wrong, but I am not giving up this position before science has donewhat it can to investigate this immense mystery We have solved many otherenigmas, including whatflames are, so there is hope that we will solve this one too

In fact, science has taken several steps toward an evidence-based model for whatconsciousness is about The task is admittedly not easy, which is why many sci-entists see it as the last frontier of science For me it is indeed the Holy Grail ofbiology

The brain consists of roughly 86 billion neurons Each can have several thousandconnections to other neurons Altogether, it is a bit like Facebook, but with tentimes more members than there are people on Earth, and where each member hasthousands of friends There is no overarching centre controlling this confusingchaos, no small lump of nerve tissue that takes leadership, but instead apparentanarchism—like the Internet Some parts of the brain are more important thanothers when it comes to generating awareness, but overall the brain has a relativelyflat organizational structure

You, that is yourfilm of life, are associated with select portions of this cauldron

of activity It seems somewhat strange that the sum of a persistent chatter betweenbillions of nerve cells generates one unified and comprehensible experience ofreality Of course it is a mystery how thisfilm is generated, but it is definitely forreal, so we should not give up our quest to understand

Many scientists have approached the problem, and together they have providedmuch insight We know quite a bit about what goes on in the brain when the mind isactive, and we have information pertaining to the“switches” that turn it on or off.Yet, the generation of brain output remains a“white area” on the map We havein-depth knowledge of nerve cells, and we describe the phenomena they give rise to

in terms of behaviour and feelings, but we know little of what goes on between

11 Descartes R The works of Rene Descartes (2010, Kindle edition).

12 See Wikipedia: http://en.wikipedia.org/wiki/Phlogiston_theory

these two levels of account Ten years ago this seemed untouchable territory, buttoday we are beginning to sense the outlines of a description.

So far, scientists studying consciousness have primarily looked for the logical processes—the neurobiological correlate In my work I have chosen aslightly different approach, I try to understand what led the process of evolutiontoward installing this feature This is, perhaps, a somewhat easier riddle to solve Infact, I do have a model that Ifind reasonably well substantiated; and this model notonly sheds light on the question of why we have consciousness, but also may help

neuro-us understand the brain processes involved Arguably, it is more important to studythe path evolution chose when adding cognizant creatures to Earth’s fauna, ratherthan the details of the contribution of various nerve cells

Sometimes when we try to peek through the window of the human mind, we get things wrong The theory of evolution helps us sort things out

It is an elephant!

There is no shortage of opinions as to what consciousness is about For Plato, itwas part of the soul, while Aristotle preferred to link it with the intellect.Present-day scientists offer more elaborate definitions The psychiatrist GiulioTononi points out that every moment of consciousness involves a huge amount

of information patched together into a unified experience.13If you focus on anorange, all sorts of data combine to form your perception, including the shape,the structure of the skin, colour, and perhaps the aroma It is all put together into

a single “unit”—the orange The mind generates a complete package thatcomes to you in the form of a three-dimensionalfilm interspersed with sound,smell, touch and personal associations He sees consciousness as a question ofthe complexity (and level of integration) of relevant information

Other researchers emphasize the possible functions of consciousness; forexample, that it evolved as a strategy aimed at orchestrating behaviour Inother words, our ability to experience life provides a basis for makingadaptive choices.14Some give up The British psychologist Stuart Sutherlandconsidered consciousness as a trait impossible to describe as to both what it isand why it exists.15 He claimed that there has never been written anythingworth reading on these topics I can appreciate the contribution made by mostscientists, with the exception of Sutherland

The various explanations remind me of an ancient anecdote from India.Four sages were blindfolded, led to an elephant, and then asked to describewhat they had in front of them Each gave a detailed description of the partthey happened to get hold of—tusks, the proboscis, a leg or the tail—butbeing blindfolded, they failed to see the relationship between these compo-nents They did not understand what they were actually examining

It seems to me that some people, scientists included, walk around

“blindfolded”, in the sense that they lack the knowledge required to ciate the wholeness of the object they are studying In order to understandliving organisms, it is essential to remove the blindfold and keep the eyeswide open Insight into the process of evolution does just that By observingphenomena, including those related to the human mind, in the light of evo-lution, you are better equipped to make a comprehensive model Perhaps withthis more comprehensive perspective, the wise men would have realized thatthe strange object they had got their hands on was indeed an elephant

appre-13 Oizumi M, Albantakis L, Tononi G From the phenomenology to the mechanisms of sciousness: integrated information theory 3.0 PLOS Computational Biology 10 (2014) e1003588.

con-14 Hameroff SR, Penrose R Conscious events as orchestrated space-time selections Journal of Consciousness Studies 18 (1996) 36 –53.

15 Sutherland S Feature selection Nature 392 (1998) 350.

A reasonable starting point for understanding the brain is to outline the manybiological functions it is required to fulfil A bit of caution is required, however,when viewing life through evolutionary glasses; and particularly when consideringthis sort of biological inventory As already pointed out, evolution has barelyattempted, and certainly not managed, to develop optimal organisms The body’svarious organs are not streamlined to fulfil particular functions Consequently, inorder to understand how evolution has shaped us we need deeper knowledge;superficial explanations easily lead in a wrong direction.

The human appendix is a good example It is presumably a leftover from thedays when our distant ancestors lived primarily on plant foods and therefore needed

an ample colony of appropriate bacteria to break down the cellulose present inplants Some believe the appendix still serves a function in that it helps maintain asuitable intestinal flora, while others look at this part of the guts as a pest andnuisance that contributes nothing except income for surgeons A feature evolutionshould have thrown overboard long ago The point is that if you try to understandthis intestinal blind alley solely in the light of its possible present role, then yourinterpretation will almost certainly be skewed

Appetite is another example Hunger and taste are important for initiatingfeeding behaviour, but these functions are not optimally designed—at least not forpresent lifestyles—which explain why such a large percentage of the populationsuffer from diabetes and obesity These problems become more comprehensiblewhen considering our evolutionary heritage Many animals, humans included, haveevolved a craving for sweet and fatty food, because they are important nutrients andsomewhat difficult to obtain Today the food industry refines products in order to hitthe human taste buds with maximum force; moreover, the only effort required is topass a trolley along the rows in a supermarket No wonder our innate urges lead tounhealthy food habits

To understand the brain, we need a model that sheds light on its evolutionaryhistory This is certainly the case when it comes to comprehending exceedinglycomplex features such as consciousness Before I try to describe the evolutionarytrajectory leading to conscious brains, I shall outline the structure and function ofthe brain

We can re flect human nature in our creations, but we will never be able to recreate the most fantastic product of evolution (From The Boboli garden in Florence)

The Brain —Your Personal Necktop

Computer

Abstract The chapter provides an introduction for those who are unfamiliar withthe inside of their head Important concepts related to the anatomy of the brain, andhow nerve circuits operate, are explained Evolution gradually added variousfunctions to the nervous system for the purpose of promoting survival and pro-creation I refer to these functions as“apps” (applications) or “modules” The textmoves on to compare the brain with a computer, as this comparison helps usunderstand both devices

The Anatomy of the Most Complex Object

In order to understand what goes on in the brain, it is important to know the basics

as to what it looks like Science has generated an anatomical“map” with names ofvarious structures, as well as a terminology that describes the processes taking place

in neurons In this chapter, I shallfirst introduce relevant features of the brain, andthen compare it with a computer I believe the comparison helps us appreciate bothtypes of devices

Thefirst part may feel a bit tedious as it is primarily about introducing severallabels and concepts I believe it is useful to have been introduced to these terms,although it is not necessary to remember their exact connotation

Unfortunately, the map is not that easy to follow For one, it is difficult to dividethe brain into distinct units; and two, various schools of science use different names

or different definitions for partly overlapping structures and concepts The situation

is further complicated by there being both an anatomical map and an even morerather inadequate and unfinished functional map The functional map is necessarilyvague because most tasks are not restricted to a particular structure

Select anatomical components, focusing on the structures I will refer to later inthe book, are indicated in Fig.1 The text moves on to briefly describe thesestructures For a better, three-dimensional and interactive map, I recommend theInternet pages Genes to Cognition set up by Cold Spring Harbor Laboratory.1

1 Try http://www.g2conline.org

© Springer International Publishing Switzerland 2016

B Grinde, The Evolution of Consciousness,

DOI 10.1007/978-3-319-43685-2_2

19

The embryonal development of vertebrate nervous systems starts with a linear tubefollowing the length of the early foetus The brain subsequently develops from fourblobs that gradually appear in the frontal part of the tube One way of portraying theadult brain is to distinguish between which of these four blobs the various structuresare derived from The remaining part of the tube gives rise to the spinal cord and theassociated nervefibres innervating the body.

The two anterior bulbs develop into the forebrain This is considered the home

of higher functions such as consciousness The main component is the cerebralcortex, which is what one can see upon removing the skull, and what most peopleassociate with the brain The power of thinking is generally assumed to dependheavily on the cortex It consists of a left and a right hemisphere, and each is furtherdivided into lobes based primarily on the deeper furrows (sulci) that are visible onthe surface The lobes are split up in sections based on presumed function, forexample, the visual cortex and the auditory cortex A large area in the innermostpart is referred to as cingulate cortex Inside that again lies the corpus callosum—a

“highway” of nerve fibres that connects the two hemispheres

The cortex, or the grey matter, is actually only a sheet of neurons some 2–4 mmthick It is attached to the white matter, which is composed primarily of nervefibres

Fig 1 Cross-section of a brain as seen from the left Structures discussed in the text are indicated The directions of the lines (up, down, left or right) suggest which (two) of the four major categories the structures belong to; for example, thalamus is part of the forebrain and of the subcortical structures While the real brain is three-dimensional, the lines end at a particular point in a two-dimensional drawing —the map is consequently a gross approximation

rather than the actual cell bodies of neurons In an analogy to electrical appliances,the grey layer constitutes the actual appliances, while white matter is simply wiringthat connects the various units Together the two layers form a 1.6 m2“blanket”that has been curled up in a somewhat disorderly fashion.

The cortex (including the white matter), as well as the underlying structuresreferred to as basal ganglia, are formed from the first bulb (the telencephalon).Together they form the cerebrum, which may be referred to as the“main brain”.The second bulb (diencephalon) gives rise to important subcortical structures such

as thalamus, hypothalamus, and (part of) the pituitary gland Some structuressurrounding the thalamus have a mixed heritage (stemming from both first andsecond bulb), the two most relevant for the present discussion are amygdala andhippocampus They contain important neural circuits associated with the generation

of good and bad feelings The amygdala is particularly associated with fear, whilehippocampus has additional functions related to memory

The third bulb (mesencephalon) is synonymous with the term midbrain It forms

a somewhat inconspicuous area in the interior part of the head It is, however, animportant“relay station” for signals going back and forth between body and brain.Information from sense organs passes here, as do impulses controlling muscularmovements

The final bulb forms the hindbrain, which includes the cerebellum (meaning

“little brain”) as well as structures in the brain stem The latter links the brain withthe spinal cord The primary function of the cerebellum is to coordinate muscleactivity It looks superficially like a smaller version of the cortex in that both havetwo hemispheres and a furrowed surface The resemblance reflects that both areformed from folded layers of nervous tissue, but while the cortex seems crumpled,the cerebellum is more neatly folded

Our giant head is primarily due to the size of the cerebrum This is the part thatexpanded most dramatically in the evolutionary lineage leading to Homo sapiens,and it constitutes the larger part of the 1.3 l human brain Does this mean that theparticular human qualities reside here? The answer is a conditional “yes”: Thecortex has important roles in consciousness and in our intellectual capacity; but as

we shall see, consciousness apparently does not depend entirely on this structure.The four bulb plan for brain architecture dates back to the early vertebrates;which means that most of the functions present in the brain have been around, insome form or another, for a long time The lower and“more primitive” part of thebrain, including the midbrain and brain stem, are required to sustain brain activity.Without them the brain cannot function In that way they are responsible for bothconsciousness and many other functions; that is, damage to sensitive areas of thebrain stem (particularly the reticular formation) means you are lost

Nerve circuits of the brain stem are presumably also responsible for moving yourattention toward dangers or other highly relevant features of the environment If youhappen to be asleep, they make sure to wake you up.2Normally you feel in charge

2 Steriade M Arousal: Revisiting the reticular activating system Science 272 (1996) 225 –226.

of what you wish to focus your mind on, but these ancient nerve circuits have thecapacity to overrule your free will It makes sense because the unconscious brainhas more information about what is going on than you do.

The“little brain” is the bigger one

The cerebellum, or little brain, constitutes, as the name suggest only 10% ofthe brain volume Surprisingly it contains 80 % of the neurons! The vastmajority of the remaining neurons are in the cortex, thus the subcorticalstructures are left with only 1 %

The main task of the cerebellum is to coordinate the use of muscles It doesnot necessarily decide on any action to be taken, but helps execute commandsstemming from your conscious mind The command centres are situatedprimarily in the motor cortex on top of the head, but orchestrating thefine-tuned activity of a large number of muscle fibres is beyond the capacity

of these centres You can decide that your right arm is to swing the racket inorder to hit a tennis ball, but to have any chance of hitting the ball the wayyou desire, the cerebellum must take care of synchronizing the musclefibresinvolved

Most people seem unaware of the complexity of this task You walkwithout as much as a thought about how to move your legs, but even on aflatsurface the coordination required is a tremendous challenge An unevensurface requires even more as to fine-tuned control Playing chess is, incomparison, an easy task We have computers that can beat the best chessplayers, but no robot is able to walk on two legs with anywhere near theelegance of a human In other words, there is a reason why the cerebellumcontains the greater share of neurons

The control of movements is, and has always been, the primary task forany nervous system—perhaps it is also the most complex task Still, you areprobably not impressed But the lack of admiration for what this clump ofnervous tissue is able to accomplish is due to your lack of knowledge Thecerebellum does not inform you about what it is up to, evolution did notfindany reason to bother your conscious brain with all the tedious details.Furthermore, you may have noticed that we humans are not particularly good

at moving our bodies; a mountain goat will run and jump around in a terrainwhere you would hardly dare to hike And as long as we consider ourselvesfar superior to these animals, the task cannot be anything worth braggingabout!?

To the extent that goats contemplate on such matters, I would guess thatthey are not particularly enthralled by our capacity to move pieces around achessboard, but do note how clumsy we are in rocky terrain Actually we doexcel in one form of coordinated muscle control—we have the most versatileand dexterous hands andfingers

The cerebellum certainly deserves more attention, but fortunately it willnot get it Whether you play tennis or go for a walk, you are best served byletting it carry out its work without your involvement and intervention.

Neuron Style Talking

The typical neuron looks like a hairy head on a thin stem (Fig.2) The hair resents dendrites that send signals in toward the head, or cell body; the stem is theaxon that passes the signal on to other cells The main function of the neurons is tocommunicate with each other by sending electrical signals through their dendritesand axons Upon reaching the next cell the signal is transferred by means ofsynapses

rep-This continuous“chatting” is the activity responsible for whatever the brain iscapable of doing—including anything from the control of breathing to reading thepages of this book Both conscious experiences and all the unconscious processesthat take place within the brain have a neurological correlate in the form of activity

in particular nerve circuits Typically, however, the correlate is exceedingly plex as there may be millions, or even billions, of neurons involved To furthercomplicate the situation, the cells are typically active even when not caring for anyparticular function

com-Actually, the brain contains a lot more than just neurons Obviously it needs ablood supply In addition it has a nerve specific support system in the form of glialcells; there are, in fact, a lot more of these around than there are neurons Thesituation is somewhat like an elite national sports team, for each active performerthere are several members of the support group The performers are the ones doingthe job, but their performance relies heavily on the backing they get Compared toother mammals, the human glial cells are bigger, and the brain contains more ofthem per neuron; it is tempting to give this“support team” part of the honour forhuman mental achievements In fact, mice where the glial cells have been switchedwith the human counterpart are“smarter” than normal mice.3As a curiosity, I mightmention that in a certain part of Einstein’s cortex the support cells were particularlyabundant.4

Signals are conducted along dendrites and axons by means of electrical pulses(in the form of ions passing into the cell and thereby causing a voltage changeacross the membrane) The synapses are either chemical or electrical In thechemical ones, which are the more common, the transmission to the next cell is by

3 Han X et al Forebrain engraftment by human glial progenitor cells enhances synaptic plasticity and learning in adult mice Cell Stem Cell 12 (2013) 342 –353.

4 Diamond MC, Scheibel AB, Murphy GM, Harvey T On the brain of a scientist: Albert Einstein Experimental Neurology 88 (1985) 198 –204.

means of messenger molecules referred to as neurotransmitters The mitters are released as the electrical signal reaches the synapse, and they are reg-istered by receptors on the receiving cell The electrical synapses, on the otherhand, stands for a more direct transfer, what may be pictured as a plug somewhatloosely stuck into an outlet.

neurotrans-Fig 2 A neuron (nerve cell) and its connections The neuron receives signals from other cells through the dendrites These impulses may or may not trigger a response in the form of a signal to

be initiated by the cell body and passed down its axon Within dendrites and the axon the impulse

is passed on by a form of electrical current; but in order to move on to another cell, the signal must pass through a synapse This typically implies the release of neurotransmitters from the sending cell; the receiving cell is triggered when the neurotransmitters bind to its receptors The lipid sheet surrounding the axon is formed by glial cells (indicated to the top right) and helps speed up the signal (Drawing Anette Mehl Landmark)

The electrical synapses stand for a fast and simple transmission, while the slowerchemical synapses allow for a lot more options in terms of modulating the signal.The neurotransmitters may, for example, either stimulate or inhibit the receiver as towhether the signal should be passed on The complexity, and opportunities,embedded in chemical synapses is reflected in the variety of chemicals involved.There are at least 60 different neurotransmitters, and a substantially larger variety ofproteins that can affect how they function The proteins include multiple receptorsfor each neurotransmitter, as well as proteins involved in the recycling and release

of neurotransmitters This system allows us to develop medications aimed at viating disorders affecting the nervous system Pretty much all the psychoactivesubstances we know act in, one way or another, by either stimulating or inhibitingthe transfer of neurotransmitter signals

alle-The most common neurotransmitters are glutamate and GABA alle-The former isstimulatory while the latter inhibits the release of further signals from the receivingcell

Each neuron may obtain input—through its incoming chemical and electricalsynapses—from more than a thousand other neurons Whether it will pass on thesignal depends on the sum of the input If the stimulatory signals are sufficientlydominating (compared to inhibitory signals), an electrical signal is sent down theaxon It is somewhat like Facebook You receive messages from various friends,and decide whether you want to pass them on to other friends If an invitation toparticipate comes from a number of sources, the neuron, and perhaps a Facebookmember, is more likely to pass it on

Also like Facebook, neurons (at least in one part of the cortex) respond morestrongly to those “closely related” (as to distance apart and/or subtype of nervecell) Actually, most of the connections of an individual cell may be more or lessdormant Apparently the brain constructs a vast number of connections, and thenuses theflexibility inherent in this somewhat redundant system to modulate activity.That is, the synapses are activated or inactivated in order for the brain to adapt, orlearn.5Having a variety of synapses preformed means new connections (requiredfor novel learning) can proceed without the lag required to grow novel axons ordendrites—just changing the relative importance of different synapses can havedrastic ramifications for the circuits involved On a negative tone, the wiring alsomeans that even if we do obtain a detailed overview of how the brain is wired,including all possible nerve circuits, we still are a far cry from having a description

of how nerve activity actually generates consciousness We would need to know theindividual role of each connection

Neurons form a grey mass (once the blood has been washed away), while areasdominated by wiring (axons and dendrites) form white matter This is because thefibres are covered with layers of cell membranes formed by glial cells Membranesconsist primarily of fat, and as you may have notices on a strip of bacon, fat is

5 Cossell L et al Functional organization of excitatory synaptic strength in primary visual cortex Nature 518 (2015) 399 –403.

generally white It is worthwhile to note that compared to our closest relatives,chimpanzees and gorillas, the human brain does not contain that much more neu-rons—the increase in size reflects primarily more connections and glial cells.During the latter part of gestation and the first two years of life, there is amassive growth in links connecting various neurons According to the Japanesescientist Tomoko Sakai this is the salient feature causing humans to outperform anyother animal in cognitive tasks.6In other words, the white matter, or the complexity

of neuron communication, is where our unique talents rest Hercule Poirot keptpointing to his“little grey cells” while he probably should have referred to his “vastwhite mass”

Even taking the complexity of chemical synapses into consideration, the working ofthe brain is reasonably simple Our present knowledge is relatively detailed andcomprehensive The miracles resulting from this activity, like the dreams and visionsyou have, are a completely different challenge They are presumably a product of theextraordinary complexity of nerve signalling between billions of neurons, butregrettably we only have vague ideas as to how these wonders are achieved.People studying complexity theory likes to make diagrams consisting of boxesconnected together with lines They will tell you that even relatively simple dia-grams, perhaps a few dozens of boxes and their connections, can give rise to highlyintricate activities No wonder the processes going on in the brain, with its billions

of boxes, are difficult to both outline and comprehend The big problem, however,

is that even if we could delineate the precise neurological activity behind a ticular percept, we still might not understand why this activity results in something

par-as intangible par-as an experience That is, how can nerve activity, however complex itmay be, give rise to consciousness?

We have just started to describe the relevant neurology This task has beenreferred to as The Easy Problem, while the leap from this description to an actualcomprehension is The Hard Problem.7Perhaps refining the description will yieldthe best possible answer science can ever offer; or perhaps a detailed account of theactivity behind consciousness will open the gates to a higher level of insight

The electrical transfer of signals involves the opening of gates for Na+-ions in thecell membrane These ions are more abundant outside the membrane, and thesubsequent influx neutralizes the typical negative electrical charge present on theinside When this happens at a particular spot in an axon (or dendrite), the effect is

to open the next Na+-gates downstream In that way the signal is passed on.Obviously, the cell needs to pump the Na+-ions out again to be ready for a newsignal, which sets a limit to the frequency of signals going down a particularfibre

6 Sakai T et al Developmental patterns of chimpanzee cerebral tissues provide important clues for understanding the remarkable enlargement of the human brain Proceedings of the Royal Society B

280 (2013) 2398 –2407.

7 Chalmers DJ The Conscious Mind (1996, Oxford University Press).

The pertinent points for the present discussion are; for one, that we can measurethis change in electrical potential across the membrane with electrodes connected to

a voltmeter; and two, that it is possible to manipulate the nerve cell intofiring, ornotfiring, by applying an electrical charge to the electrodes

In order to measure the signal as it passes through a single cell, one electrodeneeds to go inside the cell However, a large number of cells in a particular areatend tofire in synchrony The total variation in extracellular ion concentration issufficient to be measured by electrodes in that area—or even attached to the outside

of the skull The latter way of measuring is referred to as EEG cephalogram) Thefluctuations in voltage, normally measured between one elec-trode on the head and another elsewhere on the body, change more or less regularly

(electroen-as the (millions) of cells located near the electrode (which means a particular part of

Fig 3 EEG patterns associated with different brain states The neurons in any particular part of the cortex tend to fire more or less in synchrony The combined influx or outflux of ions from a large number of cells allows us to measure variations in voltage by means of electrodes attached to the head As the variations tend to be somewhat regular, we talk about oscillations The oscillations are named according to their frequency measured in Hertz (Hz), which means oscillations per second The spectrum of frequencies is divided into delta (0.1 –4 Hz), theta (4–8 Hz), alpha (8–

15 Hz), beta (15 –30 Hz), and gamma (30–100 Hz) Both the frequency and the amplitude (each vertical line to the right represents 50 µV) depend on the state of mind Note that the EEG while awake looks similar to what we find during REM sleep At the bottom is shown a brief epileptic seizure (an absence)

the cerebral cortex), eitherfire a signal or pump ions back out The oscillations areusually between 4–40 Hz (beats per second) The amplitude, the speed, and theregularity of the oscillations reflect the sort of activity going on in that particularpart of the brain Moreover, the overall pattern, which tends to be reasonablyconsistent across much of the cortex, reflects the sort of mental state you are in.Figure3 illustrates the point.

The neurons rarely stop completely their activity If they do, it most likely meansyou are dead Otherwise the chatting goes on—even when there really is nothingthat“needs to be said” This basal activity is particularly well synchronized, which

is seen on the EEG as slow and somewhat regular oscillations (such as the deltawaves associated with deep sleep)

Ever so often certain nerve circuits get particularly intense in their chatting Theset of neurons involved presumably reflects those required for a particular task,conscious or unconscious, the brain is working on The more fervent activity isrecognized on EEG as a more arbitrary pattern, largely replacing the synchrony ofthe resting state While awake, most of the cortex seems to be more or less engaged,which is seen as the more disorganized EEG pattern on top of the figure Theactivity adds up to rapid and low amplitude oscillations, what is referred to as beta

or gamma waves The amplitude is low because the neurons are less synchronized.The tendency to fire in synchrony is a key aspect of all advanced nervoussystem It is an intrinsic feature of the brain, perhaps one day it will prove to be thecore clue in our quest to understand how consciousness is generated Millions ofneurons coordinate their actions, so obviously some form of regulatory mechanism

is required Engrained in the nerve circuits there are, in other words, stimulatoryprocesses that ignite cells tofire together; as well as inhibitory processes that stopthe process from getting out of control We know a little bit about how this reg-ulation is obtained.8 The underlying neurological machinery is not constant, butamendable to external input, which means it is part of the brain’s capacity to learnand adapt to changing conditions

Sometimes this basal feature of the brain goes awry We see that in the conditionreferred to as epilepsy A part of the brain gets stuck in strong and highly syn-chronousfiring It is interesting to note that the result may be either to activate or toinactivate functions The former may cause uncontrolled jerking movements orstrange sensations; the latter, if the attack spreads to a sufficient part of the brain,may result in loss of consciousness

Although many neurons have long-distance connections, a considerable fraction

of the cells responsible for a specific task are typically localized in a particularregion It means that this region will light up as being more active than neigh-bouring parts of the brain when engaged in that particular task By measuring

8 Turrigiano G Keeping a lid on it Nature 511 (2014) 297 –298.