Functions of Cerebral Cortex

Left primary motor cortex of a person with left hemisphere dominant

• plans complex movement.

• sends its efferent fibers to basal ganglia.

• receives fibers from Broca area

• lesion causes spastic ipsilateral weakness.

• is motor homunculus

Regarding motor homunculus:

• It is primary motor cortex.

• It represents the power of individual muscles.

• The size of an area is proportional to the density of motor neurons supplying the body part.

• A toe representative area has a larger area when compared to the a finger.

• Lesion at the one of the cerebral area representing tongue causes total paralysis of the tongue.

Primary somatosensory area (areas 1, 2 and 3)

• is in the postcentral gyrus.

• receives afferent input from the thalamus.

• processes the information related with body posture.

• lesion at one side causes ipsilateral paraesthesia.

• lesion of dominant lobe causes loss of stereognosis.

Regarding the cerebral cortex:

• The primary motor cortex plans motor movement.

• The size of the motor homunculus is proportional to the neuron density supplying a muscle.

• The secondary somatosensory area regulates the body posture.

• The primary somatosensory area stores past somatic sensory experiences.

• Broca's area is the motor area for speech.

A boy picked up an object from the floor in the dark. After picking it up he realized that the object was a live snake. He then immediately dropped it. The MOST important brain area involved when he realized it is a snake is

• primary somatosensory cortex.

• secondary somatosensory cortex.

• primary motor cortex.

• secondary motor cortex.

Using a flowchart, list the brain areas and their functions when a boy searches for his pen that dropped on the floor.

List in sequence the MAIN brain areas involved and their functions when a person writes his name.

Select the areas responsible for muscle body movements.

Highlight the MAIN area involved in understanding and response in a conversation (speech production).