What Does the Brain's Cerebral Cortex Do?

The cerebral cortex is the thin layer of the brain that covers the outer portion (1.5mm to 5mm) of the cerebrum. It is covered by the meninges and often referred to as gray matter. The cortex is gray because nerves in this area lack the insulation that makes most other parts of the brain appear to be white. The cortex also covers the cerebellum.

The cortex makes up about two-thirds of the brain's total mass and lies over and around most of the brain's structures. It consists of folded bulges called gyri that create deep furrows or fissures called sulci. The folds in the brain add to its surface area and increase the amount of gray matter and the quantity of information that can be processed.

The cerebrum is the most highly developed part of the human brain and is responsible for thinking, perceiving, producing, and understanding language. Most information processing occurs in the cerebral cortex. The cerebral cortex is divided into four lobes that each have a specific function. These lobes include the frontal lobes, parietal lobes, temporal lobes, and occipital lobes.

Cerebral Cortex Function

The cerebral cortex is involved in several functions of the body including:

• Determining intelligence
• Determining personality
• Motor function
• Planning and organization
• Touch sensation
• Processing sensory information
• Language processing

The cerebral cortex contains sensory areas and motor areas. Sensory areas receive input from the thalamus and process information related to the senses. They include the visual cortex of the occipital lobe, the auditory cortex of the temporal lobe, the gustatory cortex, and the somatosensory cortex of the parietal lobe.

Between 14 billion and 16 billion neurons are found in the cerebral cortex.

Within the sensory areas are association areas that give meaning to sensations and associate sensations with specific stimuli. Motor areas, including the primary motor cortex and the premotor cortex, regulate voluntary movement.

Location

Directionally, the cerebrum and the cortex that covers it is the uppermost part of the brain. It is superior to other structures such as the pons, cerebellum, and medulla oblongata.

Disorders

A number of disorders result from damage or death to brain cells of the cerebral cortex. The symptoms experienced depend on the area damaged.

Apraxia is a group of disorders characterized by the inability to perform certain motor tasks, although there is no damage to the motor or sensory nerve function. Individuals may have difficulty walking, be unable to dress, or unable to use common objects appropriately. Apraxia is often observed in those with Alzheimer’s disease, Parkinson's disorders, and frontal lobe disorders.

Damage to the cerebral cortex parietal lobe can cause a condition known as agraphia. These individuals have difficulty writing or are unable to write altogether.

Damage to the cerebral cortex may also result in ataxia. These types of disorders are characterized by a lack of coordination and balance. Individuals are unable to perform voluntary muscle movements smoothly.

Injury to the cerebral cortex has also been linked to depressive disorders, difficulty in decision-making, lack of impulse control, memory issues, and attention problems.