Brain
The Most Complex Machine in the Universe
The human brain is the most complex and powerful machine in the universe known to humanity. The “you” that perceives, thinks, feels, and acts is just part of it. The brain receives and sends information throughout your body by way of the nervous system. With billions of nerve cells and trillions of connections, your brain is more intelligent than you can imagine, constantly carrying out millions of calculations without your awareness and allowing you to control your body and understand your perceptions almost instantaneously. The conscious mind is slow and limited compared to the brain as a whole. It can hold only a few pieces of information at a time and reason through laborious symbolic thought while the majority of your cognition is really unconscious.
The human brain can be regarded as three brains built on top of each other: the hindbrain including the top of the spinal column controls your most basic autonomic functions (heart rate, respiration, automatic movements, and overlearned movements); the midbrain at the top of the brainstem mediates between you and your voluntary movements; and the forebrain known as the cerebrum, that familiar gray bulgy shape, where your conscious and subconscious mind and personality live, where your actions are planned, and where you hear music, understand language, and dream.
The cerebrum has sections called lobes. The frontal lobes are where you plan, make decisions, and reflect on conscious thoughts. Behind the frontal lobes, in the parietal lobes, you process sensations and plan movements. In the rear of the brain, the occipital lobes process vision. On either side, there are temporal lobes involved in hearing, language, and music.
The whole brain is split down the middle into two halves joined by a bundle of nerve fibers. Nobody knows why the right side of the brain controls the left side of the body or why the left side controls the right. The left and right brains do some different tasks and reasoning: the left temporal lobes help with sequencing and are applied especially in understanding language, music, math, and logic; the right side specializes in associative reasoning, such as that used in understanding metaphors and emotions.
In the middle of the brain, below the cerebrum, cluster the amygdala, hippocampus, hypothalamus, and basal ganglia. The amygdala seems to generate basic emotions, negative ones on the left and positive ones on the right. The hippocampus is involved in triggering memories, perhaps indexing them, although we still don’t know fully how memory is stored in the brain.
The cerebrum itself creates miracles – conscious experiences and thoughts. It consists of billions of neurons, each connected on average with around 40,000 other neurons by way of long fiber-like tendrils called axons. The axons stretch away from the main body of the neuron in a process known as branching and often connect distant areas of the brain. Electrical signals called “action potentials” travel down the axons at about 100 meters per second. Between the end of an axon and the body of another nerve cell are synapses. When the signal reaches the end of an axon, it releases neurotransmitters such as the infamous serotonin into the gap known as the synapse, and these chemicals bind to receptors in the receiving neuron, completing the connection. There are about a billion synapses in bit of grey matter the size of a grain of sand.
The brain’s network is still far more complicated than anything we can yet construct or understand, but we’ve learned more about it over the past ten years than we have in any other time before. At the present time, there are several major projects underway to map it fully. Meanwhile, future technologies that will augment the human brain are also developing rapidly – especially brain-computer interfaces, so that someday we will have computer-enhanced memory, speed, and intelligence!
Quotes
“The human brain has 100 billion neurons, each neuron connected to 10 thousand other neurons. Sitting on your shoulders is the most complicated object in the known universe.” – Michio Kaku
“Everything we do, every thought we've ever had, is produced by the human brain. But exactly how it operates remains one of the biggest unsolved mysteries, and it seems the more we probe its secrets, the more surprises we find.” – Neil deGrasse Tyson
“I was taught that the human brain was the crowning glory of evolution so far, but I think it's a very poor scheme for survival.” – Kurt Vonnegut
Recommended books
The Brain that Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science by Norman Doidge
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