Function of cerebral cortex
There are three main types of activity associated with cerebral cortex-
1. Mental activity involve in memory, intelligence, sense of responsibility, thinking, reasoning, moral sense and learning.
2. Sensory perception including the perception of pain, temperature, touch, sight, hearing, taste and smell.
3. Initiation and control of skeletal muscle contraction and voluntary movement.
4. Cerebral cortex is largest site of neural integration in CNS. It plays a key role in attention, perception, awareness, thought, memory, language and consciousness.
Functional areas of brain/ cerebral cortex
Cerebral cortex has sensory areas, motor areas and association areas.
1. Sensory areas of cerebral Cortex
This area is immediately behind the central sulcus.
Sensory areas receive and interpret sensory impulses.
a. Primary general sensory area
This area is located in parietal lobe. Here sensations of pain, temperature, pressure,band touch, awareness of muscular movement and position of joints (proprioception) are perceived.
The somatosensory area of right hemisphere receives impulses from the left side of body and vice versa.
b. Primary visual areas
This area is located on medial surface of occipital lobe. The optic nerves pass from the eye to this area, which receives and interprets impulses as visual impression.
c. Primary auditory area
This area is located in superior part of temporal lobe near lateral cerebral sulcus. It perceives sound and is involved in auditory perception.
d. Primary taste area
This lies just above the lateral sulcus. Here impulses from sensory receptors in taste buds are received and perceived as taste.
e. Primary olfactory (smell) area
This area is located in temporal lobe where impulse from nose, transmitted via olfactory nerves , are received and interpreted.
2. Motor areas of cerebral Cortex
a. Primary motor area
This area is located in frontal lobe immediately anterior to the central sulcus. Cell bodies present initiate the contraction of skeletal muscle.
A nerve fiber passes downward through internal capsule to medulla obligata. Here it crosses to the opposite side and descends (move) in spinal cord.
This means that the motor area of right hemisphere of cerebrum control voluntary muscle movement on the left side of body and vice versa.
Damage to either of these neurons may result in paralysis.
2. Motor speech area; Broca's area
Motor speech area (Broca's area), located in frontal lobe just superior to lateral cerebral sulcus and controls the muscle movements needed for speech.
3. Association areas
These are connected to each other and other areas of cerebral cortex by associated tracks. They receive, coordinate and interpret impulse from sensory and motor area, permitting higher cognitive ability.
For example; tying shoelace; motor and sensory; collaboration association
a. Somatosensory association areas
b. Visual association areas
c. Auditory association area
4. Promotor area (psychomotor area)
This lies in frontal lobe immediately anterior to motor area. The neurons here coordinated movement initiated by primary motor cortex ensuring that learned pattern of movement can be repeated.
For example; lying shoelace, writing
5. Wernicke's area (sensory speech area)
Wernicke's area is located in temporal and parietal lobes. It interprets meaning of speech by recognizing the spoken words.
Understanding language important or language development.
6. Broca's area (motor speech area)
Broca's area located in inferior part of frontal lobe. Initiate muscle movement for speech and control related to production of speech.
Impulse- primary auditory cortex- wernicke's area- Broca's area- premotor area - primary motor cortex
7. Pre frontal area
The anterior association area in frontal lobe. It involved with intellect, cognition, recall and personality. It contains working memory necessary for production of ideas, judgement, reasoning and planning.
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