A day in the life of the brain

Prompted by ‘The Secrets of Consciousness’ a Scientific American ebook containing a lot of work by Christoff Koch, an American neuroscientist best known for his work on the neural bases of consciousness, I have been reading ‘A Day in the Life of the Brain’ by Susan Greenfield – who had an interesting education including A levels in Latin, Greek and Ancient History (a combination offered by the school I went to, but one which was only taken by a very select few) and whose research is focused on brain physiology, particularly on the brain mechanisms of Parkinson's and Alzheimer's diseases, but she is also known as a populariser of science. Previously noticed at references 1 and 2.

Also the media-savvy person to be found at http://www.susangreenfield.com/.

Engagingly written and including a regular cornucopia of fascinating tit-bits about the workings of brains – and those of their hosts. Furthermore, reflecting her physiological background, a lot more space is given to the chemical goings-on than is often the case in books about the brain. To what she calls the fountains of neurotransmitters; fountains which I should say are the subject of much closer control than is usually the case with their watery cousins.

The book is loosely structured by a typical working day of a typical family man (with a dog), all 24 hours of it, in nine chapters, nine chapters throughout which Greenfield uses the metaphor of throwing a stone into a pool of water, seeing how far and for how long the ripples go, to support her hypothesis that transient assemblies of neurons, assemblies which might be around for several hundred milliseconds, are the building bricks from which the mind is made, from which consciousness is made. Are a useful vehicle for discussing the workings of the mind in sickness and in health. It is the life of such an assembly, a few millimetres across at maximum extent, which is illustrated in the pictures of a young rat brain included above (taken with my telephone as the image proper has not escaped onto the internet, or at least I could not find it there). With each picture being of the same section of a baby rat brain, with the whole brain being maybe 25mm by 5mm by 5mm in vivo. Greenfield a bit vague on this last point.

Inter alia, the cornucopia serves as a check list of things that any decent account of consciousness is going to have to account for.

She does not like the idea that any particular region of the brain is responsible for consciousness. She does not, but she might well, call believers in that particular faith regionalists, rather in the way that many statisticians of the Bayesian persuasion now talk about frequentists.

Nor is she very happy about the colleagues who view the brain as a rather mechanical, albeit rather large, assembly of neurons, with neurons talking to each other through synapses in a straightforward way: if the weighted sum of synapse action is a big enough number then the host neuron fires. She tells us of the chemical complications and of neuron complications which do not fit these weighted sum models very well.

There is an interesting discussion of anaesthetics, the business of being moved from awake to asleep and back again, leading onto to something called the Bispectral Index and a contraption which you can buy to monitor the state of anaesthesia of one’s patient during an operation. See reference 3. A good example of the way in which the book sparks one’s interest in something or other, and then provides the names and references you need to go digging, should you be so inclined. Also of the power of google, which makes all this stuff more or less instantly available.

Interesting parallels are drawn between the workings of the brain of babies, of the elderly, of dreamers (in normal sleep, that is) and of schizophrenics, with small assembly size being a connecting explanatory thread – and with small assembly size being a metaphor, if not more, for small personality. Not too much there. We also have the intriguing notion that pleasure is a result of small assembly size – and of one the tricky workings of dopamine, one of the chemicals to which the book gives a fair amount of space.

While the assemblies of depressives are too big and are sometimes usefully smashed up by the use of ECT.

Assemblies which are still quite difficult to look at in the living human brain. Slices of newly dead rat cortex is one thing, a working human brain is another. But scanning technology continues to march forward; no doubt we will get there.

We are reminded of the trickiness of our sense of time. Of, for example, the way brain contrives to make the sight, sound and feel of a sensation seem simultaneous, when the signals involved are not, travelling at rather different speeds.

I learn that dreaming is not hard-wired to REM sleep. The two phenomena might well be correlated, but one can certainly have the one without the other.

We are told that babies in the womb spend most of their time asleep. Which struck me as an interesting fact. But it then struck me that I had no idea what it would mean for a baby to be asleep or how one would know. Clearly something to be looked into.

A new to me discussion of the interaction between the taste of a drink and the shape, appearance and texture of the container from which we are drinking it. An interaction which can be exploited by advertisers.

I felt that the book fell off a bit as one went through it, with more space being given to anecdotes about the brain, than to taking the discussion forward. Perhaps Greenfield was spreading herself a bit thin in these later chapters. And I had difficulty with the summing up discussion of assemblies, which was a pity as these assemblies were what the book was all about. Perhaps I was getting tired.

I also felt that she spent a fair bit of time tilting at strawmen; not that there was anything particularly wrong with what she was saying, just that it was a little unfair on colleagues.

Nevertheless, a good read with lots of good stuff. I was very pleased to have come across it.

Next stop the paper at reference 4 (for those interested, google will turn an open access version of this paper up fast enough), which will perhaps put a bit of meat on the bones of these assemblies. Then back to read this book again.

PS: an average bit of book production. My hardback copy was rather cheaply bound, as is the way with most English hardbacks these days, certainly hardbacks intended for mass consumption. Plus it smelt of ink or glue or something, rather in the way of the colour magazines which come with newspapers – which in this last case can be quite unpleasant. And the small number of diagrams on the page were a bit feeble; not very good quality grey scale. On the up side, typeface and page layout quite good, with the more tricky stuff properly confined to the extensive notes at the end, along with plenty of references, most of which google could turn up without fuss. There was also an index although I have yet to make much use of it.

Reference 1: http://psmv3.blogspot.co.uk/2016/10/second-childhood.html.

Reference 2: http://psmv3.blogspot.co.uk/2016/10/the-staff-of-life.html.

Reference 3: http://www.covidien.com/pace/clinical-education/246147.

Reference 4: Neural syntax: cell assemblies, synapsembles and readers - György Buzsáki – 2010.