FUNCTIONAL AREAS OF THE CEREBRAL CORTEX – LOCATION AND FUNCTION EXPLAINED

The cerebral cortex is the outermost layer of gray matter of brain. It regulates higher level functions like memory, thinking, language and sensory processing. It is called as the “seat of consciousness“. It is folded into gyri (elevated ridges) and sulci (depressed grooves). These infoldings increase the surface area of cerebral cortex.

The cerebral cortex has been subdivided into a number of ‘functional areas’. Broadmann has subdivided the cortex of each cerebral hemisphere into 52 functional areas. The Broadmann areas were initially based on the cytoarchitectural organization of neurons in the cerebral cortex. Many of these areas have been correlated to different functions.

MOTOR AREA (AREA 4)

LOCATION – The primary motor area (area 4) is situated in the precentral gyrus on the superolateral surface and anterior part of paracentral lobule on the medial surface.

FUNCTION – The primary motor area initiates and controls the voluntary movements of opposite half of the body.

PREMOTOR AREA (AREA 6)

LOCATION – Premotor area is located immediately in front of motor area.

FUNCTION – Planning, preparation and execution of voluntary movements.

FRONTAL EYE FIELD (AREA 8)

LOCATION – Situated in the posterior portion of middle frontal gyrus (including part of area 6 in this gyrus).

FUNCTION – Controls conjugate movements of the eyes (movement of both eyes in same direction).

BROCA’S MOTOR SPEECH AREA (AREA 44 & 45)

LOCATION – Pars triangularis and pars opercularis of the inferior frontal gyrus on the superolateral surface.

FUNCTION – Concerned with the coordination of the movements of tongue, lips, larynx and other movements employed in speech.

PREFRONTAL AREA (FRONTAL ASSOCIATION CORTEX) (AREA 9 &10)

LOCATION – The part of frontal lobe in front of premotor area.

FUNCTION – Command center for higher order “executive functions”, including planning, focus, decision-making, emotional regulation and impulse control. It is concerned with emotional reaction, intellect, foresight and judgement.

ORBITOFRONTAL CORTEX (AREA 11)

LOCATION – At the lower surface of frontal lobes, immediately above the eye sockets.

FUNCTION – Processing emotions, evaluating rewards and understanding value.

GENERAL SENSORY AREA (AREA 3, 1 & 2)

LOCATION – Postcentral gyrus on superolateral surface and posterior part of paracentral lobule on the medial surface.

FUNCTION – Area 3 receives exteroceptive (pain, temperature and touch) and conscious proprioceptive sensations. Areas 1 & 2 integrate and analyse them and are concerned with accurate localization, severity and quality of sensations.

SENSORY ASSOCIATION AREA (AREA 5& 7)

LOCATION – Superior parietal lobule on the supero-lateral surface and adjacent part of the medial surface.

FUNCTION – Is concerned with stereognosis which is the neurological ability to identify the shape, size, weight and texture of a three dimensional object using only the sense of touch, without relying on visual or auditory input. This area also involved in understanding of written or printed words.

VISUAL AREA / STRIATE AREA (AREA 17)

LOCATION – Is located on the medial surface of the occipital lobe and lies beneath posterior part of calcarine sulcus.

FUNCTION – Receives visual information from temporal retina of the same side and nasal retina of the opposite side. ( Right visual cortex receives left half of the field of vision and vice versa).

VISUAL ASSOCIATION AREA (AREAS 18 & 19)

This includes parastriate (area 18) and peristriate area (area 19).

LOCATION – Situated in occipital lobe around the visual area.

FUNCTION – It interprets the raw visual information received from the primary visual cortex. It helps in recognition of faces, objects, colors, understand spatial relationships and read text.

AUDITORY AREA (AREAS 41 & 42)

LOCATION – Middle part of superior temporal gyrus on the supero-lateral surface and the anterior transverse temporal gyrus which lies hidden in the floor of the posterior ramus of lateral sulcus.

FUNCTION – Receives basic auditory signals and interprets objective physical properties like pitch, volume and loudness. Differentiates various sound frequencies. Performs higher order processing which helps recognition of spoken language and music appreciation.

AUDITORY ASSOCIATION AREA (AREA 22)

LOCATION – Behind primary auditory area.

FUNCTION – Interprets raw sound data received from the primary auditory cortex.

VESTIBULAR AREA

LOCATION – Located deep within the lateral fissure at the junction of the posterior insula and the parietal operculum.

FUNCTION – Spatial orientation, realization of whether we are moving, turning or accelerating through space. Important role in body balance and posture control.

GUSTATORY AREA (AREA 43)

LOCATION – In the parietal operculum ventral to somato-sensory area.

FUNCTION – It receives sensory signals from taste buds and integrates them to identify basic tastes.