The brain cortex or cerebral cortex is the neural tissue that constitutes the largest and outer portion of the brain. Comprised of four major sections, the frontal, parietal, occipital, and temporal lobe, it is the epicenter of higher thought. It is responsible for awareness, language, attentiveness, and the nebulous fragments we call memory. Each of its layers is swathed with a network of neurons that help organize the central nervous system. It is about two to four millimeters thick.
Each lobe has a separate function. The occipital lobe located in the back of the brain cortex contains the primary visual cortex which is necessary for sight. Above it is the parietal lobe, which deals in sensory information and spatial recognition. At the bottom section of the brain is the temporal lobe, which process auditory stimuli. This part of the brain assists individuals in forming and understanding speech. Finally, the frontal lobe handles executive function, making decisions based on the sensory input from the other three lobes.
In addition, the brain cortex can be divided into two hemispheres by nerve fibers known as the corpus callosum. Split brain studies have shown that each hemisphere is responsible for a separate set of actions. Linear reasoning such as grammar, vocabulary, and arithmetic are performed by the left half of the brain. Estimation, approximation, speech tone, and broader contextual concepts are executed by the right half of the brain. Each hemisphere of the brain is also linked with a specific side of the body. The left half of the brain is connected to the right eye, the right arm, and right leg, and vice versa.
The brain cortex can also be classified into three areas including: sensory, motor, and association. The sensory cortex receives and processes information from the five senses. The motor areas of the brain cortex stretch from ear to ear like a hair band. They are largely responsible for voluntary movements, each hemisphere corresponding to the limbs on the opposite side of the body. Association areas heighten our interactive experience with the world around us. They support language, emotion, and abstract thought. They give us the wisdom to see ahead and to plan for what may come. More importantly, they take the visceral part of life and suffuse it with meaning. They answer who, what, when, where, how and why.
The brain cortex is also interesting simply on account of its curious construction. One of the most distinguishing features of the brain is its wrinkles. While considered an aesthetic nightmare on clothes and middle aged skin, the fissures on the brain cortex, also known as sulci, are designed to increase the total surface area, allowing for more neurons to be present. This in turn enhances the processing power of the brain, which grants us the ability to see the world with a depth and wonder. It is just another example of the engineering of nature; how it grows and evolves within the rules that govern our world.
