Tag Archives: neurons

Entropy on the brain

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‘It was the worst of times, it was the worst of times.  Again.  That’s the things about things.  They fall apart, always have, always will, it’s in their nature.’  They are the opening three lines of Ali Smith’s novel ‘Autumn’.  Ali Smith doesn’t mention entropy but that’s what she is describing.

My first-year lecture course has progressed from the first law of thermodynamics to the second law; and so, I have been stretching the students’ brains by talking about entropy.  It’s a favourite topic of mine but many people find it difficult.  Entropy can be described as the level of disorder present in a system or the environment.  Ludwig Boltzmann derived his famous equation, S=k ln W, which can be found on his gravestone – he died in 1906.  S is entropy, k is a constant of proportionality named after Boltzmann, and W is the number of arrangements in which a system can be arranged without changing its energy content (ln means natural logarithm).  So, the more arrangements that are possible then the larger is the entropy.

By now the neurons in your brain should be firing away nicely with a good level of synchronicity (see my post entitled ‘Digital hive mind‘ on November 30th, 2016 and ‘Is the world comprehensible?‘ on March 15th, 2017).  In other words, groups of neurons should be showing electrical activity that is in phase with other groups to form large networks.  Some scientists believe that the size of the network was indicative of the level of your consciousness.  However, scientists in Toronto led by Jose Luis Perez-Velazquez, have suggested that it is not the size of the network that is linked to consciousness but the number of ways that a particular degree of connectivity can be achieved.  This begins to sound like the entropy of your neurons.

In 1948 Claude Shannon, an American electrical engineer, stated that ‘information must be considered as a negative term in the entropy of the system; in short, information is negentropy‘. We can extend this idea to the concept that the entropy associated with information becomes lower as it is arranged, or ordered, into knowledge frameworks, e.g. laws and principles, that allow us to explain phenomena or behaviour.

Perhaps these ideas about entropy of information and neurons are connected; because when you have mastered a knowledge framework for a topic, such as the laws of thermodynamics, you need to deploy a small number of neurons to understand new information associated with that topic.  However, when you are presented with unfamiliar situations then you need to fire multiple networks of neurons and try out millions of ways of connecting them, in order to understand the unfamiliar data being supplied by your senses.

For diverse posts on entropy see: ‘Entropy in poetry‘ on June 1st, 2016; ‘Entropy management for bees and flights‘ on November 5th, 2014; and ‘More on white dwarfs and existentialism‘ on November 16th, 2016.

Sources:

Ali Smith, Autumn, Penguin Books, 2017

Consciousness is tied to ‘entropy’, say researchers, Physics World, October 16th, 2016.

Handscombe RD & Patterson EA, The Entropy Vector: Connecting Science and Business, Singapore: World Scientific Publishing, 2004.

Walking through exams

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As a student, in the run up to exams, I used to enjoy going out walking in the hills on my own.  This approach to exam preparation probably surprised my fellow students.  While other walkers that I came across probably thought I was mad because, in an age before mobile phones, they would see me talking to myself; because, as I walked, I was reciting material that I needed to learn for the next exam.  This technique worked for me but I have hesitated to recommend such behaviour to my students.  Now, I’ve discovered that psychologists have found that cognitive performance is improved in young adults while walking at a comfortable, relaxed speed.  This is probably connected to the neurogenesis that I wrote about in my post entitled ‘Gone walking’ on April 19th, 2017.

So, as the examination season is underway in many universities, I thought I should pass on my rather eccentric approach to exam revision.  No doubt, I’ll discover that I wasn’t so eccentric after all but none of us dared share such an unconventional approach to exam preparation.

Sources:

Schaefer et al, Cognitive performance is improved while walking: differences in cognitive-sensorimotor couplings between children and young adults, Euro J Developmental Psychology, 7:371-89, 2010.

Susan Greenfield, A Day in the Life of the Brain, London: Allen Lane, 2016.

Gone walking

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Background and lock-screen pictures have become a feature of modern life.  Your computer and mobile device were probably delivered with some pre-loaded scenes from nature and some of us personalize our devices by up-loading photographs taken on holiday or a recent excursion into the countryside.  Perhaps, we do this intuitively, because recent research has shown that immersion in nature, even at the superficial level of viewing a picture can improve brain function.  Brisk walking stimulates the production of new neurons and, when you do it in an environment enriched with natural stimuli, the connectivity and stability of connectivity between neurons is increased.  For those us whose biological systems are in terminal decline, the opportunity to retard this decline by walking in the wild is too good to miss.  I have gone to the English Lake District to produce and connect some more neurons.  I’ll be back next week – feeling hopefully creative and empowered, as well as, probably rather damp but what else can be expected from northern England in April!

For those of you who want to immerse themselves vicariously in the damp natural environment of England in the rain could read ‘Rain: Four Walks in English Weather‘ by Melissa Harrison.

Sources:

Susan Greenfield, A Day in the Life of the Brain, London: Allen Lane, 2016.

Atchley RA, Strayer DL & Atchley, Creativity in the wild: improving creative reasoning through immersion in natural settings, PloS One, 7:e51474, 2012.

Yao S et al, Physical exercise-induced adult neurogenesis: a good strategy to prevent cognitive decline in neurodegenerative diseases? Biomedical Research Intl., 2014, 403120.

Olson KA et al, Environmental enrichment and voluntary exercise massively increase neurogenesis in the adult hippocampus via dissociable pathways, Hippocampus, 16:250-260, 2006.

Is the world incomprehensible?

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For hundreds of years, philosophers and scientists have encouraged one another to keep their explanations of the natural world as simple as possible.  Ockham’s razor, attributed to the 14th century Franciscan friar, William of Ockham, is a well-established and much-cited philosophical principle that of two possible explanations, the simpler one is more likely to be correct.  More recently, Albert Einstein is supposed to have said: ‘everything should be made as simple as possible, but not simpler’.  I don’t think that William of Ockham and Albert Einstein were arguing that we should keep everything simple; but rather that we should not make scientific explanations more complicated than necessary.  However, do we have a strong preference for focusing on phenomena whose behaviour is sufficiently uncomplex that it can be explained by relatively simple theories and models?  In other words, to quote William Wimsatt, ‘we tend to ignore phenomena whose complexity exceeds the capability of our detection apparatus and explanatory models’.  Most of us find science hard; perhaps, this is not just about the language used by the cognoscenti to describe it [see my post on ‘Why is thermodynamics so hard?‘ on February 11th, 2015]; but, more about the complexity of the world around us.  To think about this level of complexity requires us to assemble and synchronize very large collections of neurons (100 million or more) in our brains, which is the very opposite of the repetitive formation of relatively small assemblies of neurons that Susan Greenfield has argued are associated with activities we find pleasurable [see my post entitled ‘Digital hive mind‘ on November 30th, 2016].  This might imply that thinking about complexity is not pleasurable for most us, or at least requires very significant effort, and that this explains the aesthetic appeal of simplicity.  However, as William Wimsatt has pointed out, ‘simplicity is not reflective of a metaphysical principle of nature’ but a constraint applied by us; and which, if we persist in its application, will render the world incomprehensible to us.

Sources:

William C. Wimsatt, Randomness and perceived randomness in evolutionary biology, Synthese, 43(2):287-329, 1980.

Susan Greenfield, A day in the life of the brain: the neuroscience of consciousness from dawn to dusk, Allen Lane, 2016.