LECTURE FUNCTIONAL AREAS OF CEREBRAL CORTEX
LECTURE OUTLINE 2: 3 DIVISIONS OF FUNCTIONAL AREAS OF CEREBRAL CORTEX
Division Location Brodmann’s Functions Homunculus Damage/ lesion
area effect
MOTOR AREAS Anterior to central Control voluntary movement of
sulcus in frontal lobe muscles on contralateral side of
body
1 Primary motor area (M-I) On precentral gyrus 4 i) Controls movement of muscles Somatotopic Damage of M-I in
extending to anterior in contralateral side of head & arrangement one hemisphere
part of paracentral body (Inverted motor result in paralysis of
lobule ii) Initiates or execute voluntary homunculus of contralateral side
movements precentral gyrus)
2 Supplementary motor area (M-II) On medial surface of 6 i) Programme the sequence and No permanent loss
frontal lobe on the (on medial coordination of movement of movement if
medial frontal gyrus surface of occurring on two sides of body damaged
frontal ii) Movement of contralateral
lobe) limb but need stronger stimulus
than M-I
3 Premotor cortex (PMC) On posterior parts of Most of BA i) Controls axial & proximal limb Causes difficulty in
the superior, middle, 6 musculature in postural performing skilled
and inferior frontal (on lateral adjustment movements (only
gyri surface of ii) Guides the body & upper limbs little loss of strength)
(anterior to the M-I frontal turning toward a desired
area) lobe) direction based on sensory inputs
4 Frontal eye field In middle part of 8 i) Produces voluntary conjugate
frontal gyrus movements of eyes toward
opposite side
ii) Coordination of eye
movements particularly in
voluntary tracking of a moving
object
arrabi hl 1
, SENSORY AREAS Provide conscious awareness of
sensation
i) Each sensory area receives a
specific sensory
ii) All sensory information (except
olfaction) must pass through
thalamus before reaching sensory
areas of cerebral cortex
1 Somatosensory In postcentral gyrus 3, 1, 2 To produce conscious awareness The opposite half of the
(somesthetic) Primary (lateral surface) and of the sensory information. It body is represented as
cortex somatosensory posterior part of receives: inverted homunculus.
cortex (S-I) paracentral lobule i) Tactile (cutaneous) sensation – *Pharynx & tongue
(medial surface) pain, touch, temp. vibration & (most inferior)
pressure *Thigh (most superior)
ii) Proprioceptive sensation *Foot & anogenital
(medial)
Secondary In most inferior For conscious perception of Pseudothalamic pain
somatosensory aspect of postcentral noxious stimuli (burning/icelike pain
cortex (S-II) gyrus & parietal associated with
operculum (superior absence of painful
bank & depth of sensation)
lateral sulcus)
Somatosensory In superior parietal 5&7 For perception of shape, size, Bilateral lesion: Optic
association lobule texture, and identification of ataxia (e.g., Pouring
cortex object by contact. water outside glass)
Unilateral lesion:
neglect contralateral
half of body & visual
space
arrabi hl 2
LECTURE OUTLINE 2: 3 DIVISIONS OF FUNCTIONAL AREAS OF CEREBRAL CORTEX
Division Location Brodmann’s Functions Homunculus Damage/ lesion
area effect
MOTOR AREAS Anterior to central Control voluntary movement of
sulcus in frontal lobe muscles on contralateral side of
body
1 Primary motor area (M-I) On precentral gyrus 4 i) Controls movement of muscles Somatotopic Damage of M-I in
extending to anterior in contralateral side of head & arrangement one hemisphere
part of paracentral body (Inverted motor result in paralysis of
lobule ii) Initiates or execute voluntary homunculus of contralateral side
movements precentral gyrus)
2 Supplementary motor area (M-II) On medial surface of 6 i) Programme the sequence and No permanent loss
frontal lobe on the (on medial coordination of movement of movement if
medial frontal gyrus surface of occurring on two sides of body damaged
frontal ii) Movement of contralateral
lobe) limb but need stronger stimulus
than M-I
3 Premotor cortex (PMC) On posterior parts of Most of BA i) Controls axial & proximal limb Causes difficulty in
the superior, middle, 6 musculature in postural performing skilled
and inferior frontal (on lateral adjustment movements (only
gyri surface of ii) Guides the body & upper limbs little loss of strength)
(anterior to the M-I frontal turning toward a desired
area) lobe) direction based on sensory inputs
4 Frontal eye field In middle part of 8 i) Produces voluntary conjugate
frontal gyrus movements of eyes toward
opposite side
ii) Coordination of eye
movements particularly in
voluntary tracking of a moving
object
arrabi hl 1
, SENSORY AREAS Provide conscious awareness of
sensation
i) Each sensory area receives a
specific sensory
ii) All sensory information (except
olfaction) must pass through
thalamus before reaching sensory
areas of cerebral cortex
1 Somatosensory In postcentral gyrus 3, 1, 2 To produce conscious awareness The opposite half of the
(somesthetic) Primary (lateral surface) and of the sensory information. It body is represented as
cortex somatosensory posterior part of receives: inverted homunculus.
cortex (S-I) paracentral lobule i) Tactile (cutaneous) sensation – *Pharynx & tongue
(medial surface) pain, touch, temp. vibration & (most inferior)
pressure *Thigh (most superior)
ii) Proprioceptive sensation *Foot & anogenital
(medial)
Secondary In most inferior For conscious perception of Pseudothalamic pain
somatosensory aspect of postcentral noxious stimuli (burning/icelike pain
cortex (S-II) gyrus & parietal associated with
operculum (superior absence of painful
bank & depth of sensation)
lateral sulcus)
Somatosensory In superior parietal 5&7 For perception of shape, size, Bilateral lesion: Optic
association lobule texture, and identification of ataxia (e.g., Pouring
cortex object by contact. water outside glass)
Unilateral lesion:
neglect contralateral
half of body & visual
space
arrabi hl 2
