Over the years, our understanding of the brain has expanded exponentially, although we still have a lot more to learn, here is what we know so far about the brain, as well as some of its aspects that remain to be understood.
Brain size: Though the brain size varies widely, depending on age, sex, and overall body mass, studies have suggested that, on average, the adult male brain weighs about 1,336 grams, while the adult female brain weighs around 1,198 grams. Relative to other species, the human brain has the largest number of neurons, which are specialized cells that store and transmit information by electrical and chemical signals. Neuroscientist estimates the number of neurons to be around 86 billion.
Brain components: The human brain along with the spinal cord make up the central nervous system. The brain itself has three main parts: the cerebellum, cerebrum and the brain stem, which acts as a relay center connecting the cerebrum and cerebellum to the spinal cord. The cerebellum, located at the back of the brain, is deeply involved in regulating movement, motor learning, and maintaining equilibrium.
The cerebrum is the largest part of the brain and fills up most of the skull; it houses the cerebral cortex (that has a left and a right hemisphere separated by a long groove) and other, smaller structures, all of which are variously responsible for conscious thought, decision-making, memory and learning processes, communication, and perception of external and internal stimuli.
Brain composition: Brains are made of soft tissue, which includes gray and white matter, containing nerve cells, non-neuronal cells that help to maintain neurons and brain health, and small blood vessels. They have a high water content as well as a large content of fat (nearly 60%). The brain of the modern-day human is globular, unlike the brains of other early hominids, which were slightly elongated at the back.
Brain hunger: Despite the human brain weighing only around 2 percent of body mass, it uses up nearly 25 percent of the energy that the body requires to function. While most of this energy is believed to be used in maintaining ongoing thought and bodily processes, some of it is probably invested in maintaining the health of brain cells. Also, quite inexplicably, the brain uses up a lot of energy during what is known as the ‘resting state’, when it is not involved in any specific, targeted activities. Some researchers contend that the energy spent ‘doing nothing’, is actually expended towards assembling a ‘map’ of accumulating information and experiences that we can fall back on when making decisions in our day-to-day lives later.
Brain usage: The notion that humans typically use only 10 percent of their brain capacity, and that if we could utilize the unused 90 percent we could unlock amazing abilities, is actually a myth. In fact, human beings use most of the brain pretty much all of the time. Brain scans have also shown that we use pretty much all of our brains all of the time, even when we are asleep — though patterns of activity, and the intensity of that activity, might differ depending on what we are doing and what state of wakefulness or sleep we are in.
Right and left brain: Another prevailing myth is that a person’s personality is determined by whether they are ‘right’ or ‘left’ brained. Allegedly, left-brained people are more mathematically inclined and analytical, while right-brained people are more creative.
While it is true that each of our hemispheres has slightly different roles, there is no ‘dominant side’ which determines a person’s personality and abilities. Instead, research has revealed that people use both brain hemispheres pretty much in equal measure. However, it is true that the left hemisphere of the brain is more concerned with the use of language, while the right hemisphere is applied more to the intricacies of nonverbal communication.
Aging brain: As we age, parts of our brain begin to shrink naturally and we gradually lose neurons. The frontal lobe and the hippocampus start shrinking when we reach 60 or 70 years, making it challenging to learn new things or to multi-task. However, the good news is that, new research suggests adult brains can produce around 700 new neurons per day in the hippocampus through a process called neurogenesis.
Despite many advances in research and clinical technology, a lot of questions about the brain remain unanswered. For example, we still do not quite understand how complex information is processed in the brain. Nevertheless, the next time you pick a flower and smell it, think how much you owe the brain for helping us cope with life and to understand the world around us.