How do we think? Some Musings…

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One of the great puzzles of neuroscience is to determine how we think.  This seemingly easy question is far more complex than could have been envisaged in close inspection, and is not simply an algorithmic amalgamation of neuronal firing patterns.  There has, obviously, been considerable research as to how memories are formed and encoded by increased complexity and density of neuronal connections.  Nevertheless, how is thinking about a complex task generated or even completed? It would appear that different tasks are taken up by various brain regions.  It would seem that thinking related to strong sensory stimuli seem to have high representation and can dominate thinking networks. Put another way, thinking that involves the coding of considerable emotional or affective states, is associated with high amounts of brain activation and energy consumption.  Intriguingly, for an organ weighing just about 3 pounds to consume 20 – 25% of the bodies’ energy would suggest that this activity must have been prioritized by evolution to increase our ability to survive compared with other animals.  Indeed, it would appear that highly emotionally charged thinking processes can interrupt and distract those related to more cooler tasks like doing arithmetic; thus enhancing our ability to recognize and flee from danger. Despite the high energy consumption of the brain, and that its vast networks are not always activated, it is fascinating that it is not really possible to think about more than one set of complex items at a time.  This would seem to imply that the brain recruits different neuronal circuits, perhaps even for related tasks, and it is so highly plastic, that it virtually moulds emotion into thinking. Put simply, this would imply that the brain is constantly learning to think, and by that concept, would imply that increased learning and mental effort would enhance thinking.  Paradoxically, however, the evidence that continuous global mental energy expenditure enhances thinking is difficult to prove.  For example, playing 10 hours as opposed to 5 hours of chess a day might not actually result in greater capacity to think. Interestingly, given the vast resources the brain actually has in neuronal capacity – greater and more complex than our Milky Way – it would not seem to be an inexhaustible resource.  Indeed, even high focus on specific mental tasks can be associated with possible effects that would appear mentally fatiguing, even though relatively little of the brain’s resources is actually being used.  There are other seemingly trivial yet intriguing aspects of brain energy expenditure. Why does it not seem possible, for example, just by thinking, to actually reduce body weight significantly?  The obvious explanation is that we do not seem able, like physical exercise, to increase brain energy consumption just by its increased utilization.  But there are probably even better neuro-dynamic explanations that are yet to be discovered. One common myth that is easy to dispel is that we do not seem to think like computers.  Even the most powerful computers nowadays mostly rely on fixed processes.  In the future, we might well see computers that not only learn and think adaptively using advanced artificial intelligence, and when ethics permit, might actually include a symbiosis of in-silico and neuronal tissue.  Or, will we reach a stage in computer development that  would our brains receive cybernetic devices to improve its performance? When all is said and done, thinking is both marvelous as it is mysterious, and might well remain so for quite some time.  We actually need to learn to think. Understanding how we think is one of the great barriers for us to conquer in the next generation of neuroscientific development.