Why does our brain work the way it does?
This question is one closely related to the field of medicine known as neurology. "Neuro" commonly talks about the nerve and diseases of the nerve. A neurologist is a doctor who specializes in neurology is called a neurologist. The neurologist treats disorders that affect the brain, spinal cord, and nerves. Now off to today's question, "why does our brain work the way it does?". Scientifically speaking, our brain has billions of nerve cells, arranged in a particular pattern, which coordinates the way we think. Our brain is divided separately into different places.
Firstly, the largest part of our brain, the cerebrum. It is the outermost layer, it is what we imagine when we hear the word "brain". It is the place where all the folding takes place. The cerebrum is divided into two halves (hemispheres) by a deep fissure. The hemispheres communicate with each other through a thick tract of nerves, called the corpus callosum, at the base of the fissure. In fact, messages to and from one side of the body are usually handled by the opposite side of the brain.
Our brain is further divided into frontal lobes, parietal lobes, occipital lobes, temporal lobes. The frontal lobes control thinking, planning, organizing, problem solving, short-term memory and movement. The parietal lobes interpret sensory information, such as taste, temperature and touch. The occipital lobes process images from your eyes and link that information with images stored in memory. The temporal lobes process information from your senses of smell, taste and sound. They also play a role in memory storage.The cerebellum is a wrinkled ball of tissue below and behind the rest of your brain. It works to combine sensory information from the eyes, ears and muscles to help coordinate movement.
The cerebral cortex of the human brain is highly convoluted, meaning it has many folds and creases. These convolutions allow a large surface area of brain to fit inside our skulls. Because of this brain shape, our brains can have billions of neurons and we can still have relatively small heads! Many animals do not have brain shapes like ours. Instead, their brains are smooth, with no sulci (grooves) or gyri (the bulges seen on the outer surface). However, in a new Science paper, Anjen Chenn and Christopher A. Walsh show that the normally smooth mouse brain can become folded and convoluted, much like human brains, if the production of a certain protein is changed.
The scientists studied mice that were genetically engineered to overexpress a protein called beta-catenin. Beta-catenin was already known to be involved in mammalian brain development, and it appeared to be connected to some human cancers. Therefore, it was logical that it might be important for the regulation of cell numbers. When the researchers looked at mouse embryos that contained an excess of beta-catenin, they found that the brains were abnormally large. Additionally, the brains were now folded, and therefore had an even larger surface area. Although the surface area of these mouse brains increased, the thickness of the brain tissue remained about the same.
Chenn and Walsh were interested in why the brains were bigger. Were cells dividing more quickly? Were fewer cells dying? The answer to both of these questions was "No." During development, young cells are unspecific. In other words, they have the potential to become many different types of cells. The cells continue to divide until they "choose" to become a specific type of cell. In the engineered mice with more beta-catenin, many of the young cells chose to stay in the cell cycle and keep dividing longer than usual. Eventually, they chose to become mature neurons, but because they divided for a longer period of time, there were many more of them. This increased number of neurons resulted in a larger brain volume and in an increased surface area.
Fun fact: Myths have it that our brain folds or convolutes whenever we think or "rack" (brain storm) our brains. However our brain also convolutes to allow it fit in our skull.
Source
- Mayo Clinic
- Neuro science for kids
