The Cerebral Cortex
The cerebral cortex, the largest part of the mammalian brain, is the wrinkly, grey outer covering of the cerebrum. While the cortex is less than 1/4" thick, it is here that all sensation, perception, memory, association, thought, and voluntary physical actions occur. The cerebral cortex is considered the ultimate control and information-processing center in the brain.
The cortex is made of layers of neurons with many inputs; these cortical neurons function like mini microprocessors or logic gates. It contains glial cells which guide neural connections, provide nutrients and myelin to neurons, and absorb extra ions and neurotransmitters. The cortex is divided into four different lobes - the parietal, occipital, temporal, and frontal lobes (Figure 1) - which will be discussed in detail in the following section.
Relationship to the cerebrum
Beneath the cerebral cortex, the inside of the cerebrum beneath is comprised of white matter made up of myelinated neurons that carry information from one part of the brain to another. The cerebrum is the large, main part of the brain, which serves as the main thought and control center. It is the seat of 'higher level' thought, like emotions and decision making, as opposed to 'lower level' thought, like balance, movement, and reflexes.
The cerebrum is divided by the longitudinal fissure into a right hemisphere and a left hemisphere. These hemispheres each have their own unique 'persona'. People who are described as being more 'right brained' are often more intuitive; whereas people who are more 'left brained' are often more logical. Each cerebral hemisphere perceives and controls the opposite side of the body.