But that crucial 1-2% difference is mainly the genetic factors affecting the brain – especially for its relationship functions. Human DNA is about 98-99% identical to chimpanzee DNA. Your brain is the product of 3.5 billion years of intense evolutionary pressure, including 2.7 million years as tool-using hominids and over 100,000 years as homo sapiens. In the deepest sleep, and even in such a deep coma that artificial life support is needed, the brain is always humming away, always “on,” with billions of neurons firing every minute, in order to keep your body alive and ready for immediate survival activities.Ĭonsequently, your brain – about 2% of the weight of a typical person – consumes about 20% of the oxygen and glucose circulating in your blood. The slower, more congealed turgid stuff that we call thought is just the observable tip of an iceberg of lightning quick electrical, chemical – and possibly quantum – activities. Most brain activity is lightning fast and forever outside of awareness.
In the half second it takes you to clap your hands, billions of synapses have activated in your brain. Neurons typically fire 5 – 50 times a second, with millions and even billions of them pulsing in harmony with each other many times a second the electrical currents of that pulsing are revealed as brain waves in an EEG. More complex than the climate of our planet or an exploding star. In sum, your brain is literally the most complex object known in the universe. That’s why thinking about something like a dripping faucet brings to mind something seemingly random like your grandmother’s great oatmeal cookies. Nonetheless, because of that connection, when the first circuit fires the second is more likely to fire as well. Wandering stream of consciousness – Again to simplify: the C neuron in the circuit just mentioned could easily be part of another circuit having nothing to do with the first one.The dynamic and “chaotic” behavior of complex systems: it’s not random, but it is inherently unpredictable.The recursive processes needed for self-regulation – and which, after many layers and lots of evolution - allow you to think about your own thinking.With all that connectivity, circular loops are routine in which – to simplify – the A neuron triggers B which lights up C which signals D which triggers A. Like a computer network built from five hundred trillion transistors, each representing a “bit” of information depending on whether it is “on” or “off.”Īdding up all possible combinations of 100 billion neurons firing or not, the number of potential states of that neuronal network is approximately 10 to the millionth power: one followed by a million zeros. On average, each of the 100 billion neurons in your head has about 5000 connections with other neurons, creating a huge network of about 500 trillion synapses. This tip has increased in complexity dramatically throughout evolution, indicating that the development of this fundamental crossroads has been vital in what has made us human. The receiving side of a synapse – the sensitive tip of the spike called a dendrite – is the most molecularly complex structure in the body, built from 1100 different proteins. To simplify a little, the sum of all the excitatory and inhibitory signals a neuron receives from its “upstream” neurons determines whether it will fire itself – sort of like the dominant message from a crowd of people all shouting “go!” or “stop!” When a neuron fires, sending neurotransmitters across the synapse – the tiny space between it and another neuron it is connected with – that either excites or inhibits the receiving neuron. The gray matter is where most of the action is for conscious experience. One hundred billion of those are in the “gray matter,” a kind of “skin” of nerve tissue wrapping around the “white matter” that comprises most of the bulk of the brain. ComplexityĪlthough your brain isn’t heavy – about three pounds of soft, gooshy tissue like tapioca pudding – it has about 1.1 trillion cells altogether.
For more information, check out the resources on the WiseBrain website. This is a summary of the key features and functions of your wonderful brain.
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