Brain complexity: importance analyzed (Introduction)

by David Turell , Friday, September 16, 2016, 14:30 (2990 days ago) @ David Turell

New mathematical approaches to brain complexity help diagnosis: - https://aeon.co/ideas/the-fugue-of-life-why-complexity-matters-in-neuroscience?utm_sour... - "A concept called self-organised criticality (SOC), first described in 1987 by the physicists Per Bak, Chao Tang and Kurt Wiesenfeld of the Brookhaven National Laboratory in New York, helps to explain. To understand SOC, imagine a sandpile at the beach. If we add sand to the sandpile until the slope is too steep to support more sand, avalanches erupt, ranging in size from a few grains to a large portion of the pile. These avalanches result from a slow process (adding sand) that builds energy, and a fast process (the force of gravity overcoming the force of friction) that dissipates energy. The instability of the sandpile is a complex state that is formally known as criticality. As with complex brain activity, avalanches exist at all spatial and temporal scales and cannot be understood merely by studying constituent parts of the system. - "Like the sandpile, the brain is poised at the edge of criticality. But while sandpile avalanches do not process information in any meaningful way, neural avalanches - cascades of complex brain activity described by researchers at the US National Institute of Mental Health in 2003 - might be vital for a brain that transitions rapidly between many cognitive states and motor programmes. In other words, in a living system such as the brain, SOC is not disorder but, rather, a mechanism for carrying out rapid computations, not unlike the self-organising behaviour of financial markets rapidly ‘determining' prices, or electorates rapidly transitioning between political majorities. For the brain, a loss of criticality - and, thus, of complex behaviour - is pathological. - "It is unsurprising, then, that complex behaviour observed in electrical brain activity might serve as a useful biomarker of disease risk or prognosis. This doesn't mean that having a crazy, erratic brain signal is healthy! A useful definition of complexity is a balance between opposing tendencies such as order and disorder, or stability and instability. Using mathematical tools that quantify complexity, researchers at leading institutions across the globe have already identified potential biomarkers of psychiatric disorders, including autism and schizophrenia, in EEG signals recorded non-invasively from the scalp. - *** - "Imagine anatomical brain regions as Facebook friends connected by anatomical fibres. As in social networks, 20 per cent of the regions (or Facebook profiles) account for 80 per cent of the connections. Like social networks, brain regions form densely interconnected ‘cliques', mini-networks embedded within the larger network. These cliques are often part of still larger cliques, a condition known as modularity. On Facebook, your closest friends might be part of a larger, looser collection of friends, who in turn are part of an even larger community, such as a town or university. In both social networks and brains, it is the complex interactions between parts that give rise to phenomena at all scales. Both brains and social networks are somewhat analogous to an ant colony: organised activity occurs across spatial scales, and you cannot study just one ant to grasp the colony as a whole. - *** - "In fact, across all scales of brain organisation and activity, scale-free distribution abounds. Recordings of electrical activity from the scalp and cortex fluctuate such that no average frequency exists. Scale-free distribution has been shown in measurements of neural spiking, opening and closing of ion channels, and neurotransmitter release at the synapse. - "While it is unclear exactly which mechanisms give way to neural complexity and healthy behaviour, keeping track of complexity is important to understanding and identifying brain disorders such as epilepsy, autism and schizophrenia. Measuring the complexity of brain activity could soon allow doctors to predict which infants will develop autism and how schizophrenia patients will respond to medication. As the physicist Emerson Pugh said: ‘If our brains were simple enough for us to understand them, we'd be so simple that we couldn't.'" - Comment: The most complex object in the universe did not develop by chance. it only took six million years of 3.8 billion years of life. This article explains some of he functionality, but not consciousness.