Cerebral cortex

The cerebral cortex is a brain structure in vertebrates, including humans. It is the outermost layer of the cerebrum and has a grey color. (Hence the name "gray matter". Gray matter is formed by neurons and their fibers, and white matter below the gray matter of the cortex is formed predominantly by nerve fibers interconnecting cortical areas with each other and with subcortical structures.) The human cerebral cortex is 2-4 mm (0.08-0.16 inches) thick and is folded.

Related Topics:
Brain - Vertebrate - Human - Cerebrum - Grey

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In the "higher" animals (especially the higher mammals), the surface of the cerebral cortes becomes folded. This creates grooves on the surface of the brain called "sulci" (singular = "sulcus"). The bumps or ridges on the surface of the brain are called "gyri" (singular = "gyrus"). The folding of the cortex increases the cortical surface area. The cerebral cortex, made up of four lobes, is involved in many complex brain functions including memory, attention, perceptual awareness, "thinking", language and consciousness.

Related Topics:
Animal - Mammal - Fold - Sulci - Memory - Attention - Awareness - Thinking - Language - Consciousness

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The cerebral cortex receives sensory information from many different sensory organs eg: eyes, ears, etc. and processes the information.

Related Topics:
Sensory - Information - Organ - Eye - Ear

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Areas that receive that particular information are called sensory areas. The two hemispheres receive the information from the opposite sides of the body. Sensory information is relayed to the cortex by the thalamus.

Related Topics:
Areas - Body - Thalamus

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Parts of the cortex that receive this information are called primary sensory areas.

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Other areas receive impulses from the primary sensory areas and integrate the information coming in from different types of receptors (i.e., modalities). These are often called association areas and make up a great deal of the cortex in all primates, humans included. Thus, the cortex is commonly descrbed as comprised of the primary sensory areas, the motor areas and the association areas.

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Association areas can be grouped the following way:

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• in the parietal, temporal and occipital lobes. It is involved in producing our perceptions resulting from what our eyes see, ears hear and other sensory organs tell us about the position of different parts of our body and relate them to the position of other objects in the environment
• in the frontal lobe. Called prefrontal association complex and involved in planning actions and movement, as well as abstract thought
• in the limbic association area. Involved in emotion and memory

In humans, the association areas of the left hemisphere, especially the parietal-temporal-occipital complex are responsible for our understanding and use of language.

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The motor areas are located in both hemispheres of the cortex. They are shaped like a pair of headphones stretching from ear to ear. The motor areas are very closely related to the control of voluntary movements, especially fine fragmented movements performed by the hand. The right half of the motor area controls the left side of your body and vice versa.

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Two areas of the cortex are commonly referred to as motor:

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• Primary motor cortex: Executing voluntary movements
• Secondary motor areas in premotor cortex: Selecting voluntary movements

In addition, motor functions have been described for

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• Posterior Parietal Cortex: Guiding voluntary movements in space
• Dorsolateral Prefrontal Cortex: Deciding which voluntary movements to make according to higher-order instructions, rules and self-generated thoughts
 
Cerebral cortex: Development ►