Cerebral Cortex -- The Outer Layer of the Brain
The cerebral cortex is the outer layer of the cerebrum section of the brain. The Cerebral cortex consists of the outer two millimeters of gray matter covering the cerebral hemispheres. The surface of the cerebral cortex is folded with more than two-thirds of it buried in crevices or grooves, called "sulci".
The cerebral cortex can be divided into four lobes: temporal lobe, occipital lobe, parietal lobe and frontal lobe.
The temporal lobe is located on both cerebral hemispheres on the left and right side of the brain. It is involved in auditory perception and is home to the primary auditory cortex.
The occipital lobe is the smallest of four lobes, and is located at the rear of the brain. It contains the visual cortex, and is responsible for visual processing.
The parietal lobe is located above the occipital lobe and behind the frontal lobe. It is responsible for integrating sensory information from various parts of the body, and is involved in the body movements such as the manipulation of objects. The parietal lobe is also involved in the knowledge of numbers and their relationships. This lobe is divided into two hemispheres- left and right. The left parietal hemisphere is dominant in right-handers, and is involved in language and math. The right parietal hemisphere is dominant in left-handers, and is involved in image processing and understanding of spatial relationships such as maps.
Regions of the Cerebral Cortex
The frontal lobe, as the name implies, is located at the front of each cerebral hemisphere. Relative to the other lobes, it is located in front of the parietal lobes, and above and in front of the temporal lobes. The frontal lobe is involved in higher mental functions. For example, the ability to recognize future consequences of current actions, or choosing between good and bad actions. The frontal lobe is involved in determining appropriate social behaviors and controlling emotions to fit socially acceptable norms.
The frontal lobe also plays an important part in retaining longer term memories, especially those memories associated with emotions.
Functionality of the cerebral cortex can be divided into the motor cortex, and the sensory cortex. The motor cortex is part of the cerebral cortex involved in controlling voluntary motor functions. The motor cortex is located in both hemispheres of the cortex. The motor areas control voluntary movements of the body, such as fine movements of the hand. The right half of the motor cortex controls the left side of the body, and the left side of the motor cortex controls the right side of the body.
The sensory cortex is involved in receiving and processing information from the skin and other sense organs. This includes the sense of vision, hearing and touch. Like the motor areas, the sensory areas are located on both hemispheres of the brain. Also, like the motor cortex, the right sensory cortex receives information from the left limbs, and the right visual cortex receives information from the left eye. The left sensory and visual cortex receives information from the right side of the body. The amount of cerebral cortex dedicated to a function is directly related to the number of nerves on the body part being sensed. For example, areas of the body with lots of sensory nerves, such as the fingertips and lips, have more cortical area to process the sensations.