2. OBJECTIVES
Areas in Frontal lobe
Areas in Parietal lobe
Areas in Occipital lobe
Areas in Temporal lobe
Clinical Implications
3. INTRODUCTION
Cerebral cortex is folded into gyri which are separated from
each other by sulci.
This pattern increases the surface area of the cortex.
4. GYRI AND SULCI
Central sulcus separates frontal lobe and parietal lobe
Lateral sulcus separates frontal lobe from temporal lobe
5.
6.
7.
8. AREAS OF BRAIN
• The cortex can be divided into three functionally distinct areas:
• Sensory
• Motor and
• Associative.
The motor cortex is divided into three areas:
1. Primary motor cortex: Main contributor to the generation of neural
impulses that control the execution of movement.
2. Premotor cortex: Located anterior to the primary motor cortex and
responsible for some aspects of motor control.
3. Supplementary motor area (SMA): Functions include internally
generated planning of movement, planning of sequences of movement,
and the coordination of the two sides of the body. It is located on the
midline surface of the hemisphere anterior to the primary motor cortex.
9. AREAS OF BRAIN
The main sensory areas of the brain include the primary auditory
cortex, primary somatosensory cortex, and primary visual cortex.
• primary somatosensory cortex: The main sensory receptive area for
the sense of touch.
• primary auditory cortex: A region of the brain that processes sound
and thereby contributes to our ability to hear.
• primary visual cortex: Located in the posterior pole of the occipital
cortex, the simplest, earliest cortical visual area. It is highly specialized
for processing information about static and moving objects and is
excellent in pattern recognition.
Associative areas of the cortex integrate current states with past states
to predict proper responses based on sets of stimuli.
11. Primary Motor Cortex (M1, Brodmann
area 4)
The primary motor cortex is located on the precentral
gyrus just rostral to the central sulcus.
It is the source of cortical neurons that will project to the
brainstem and spinal cord to activate neurons involved in
the control of voluntary movements.
It receives input from the neighboring primary
somatosensory area (S1, on the postcentral gyrus) and
premotor cortex, as well as from the ventral lateral
nucleus of the thalamus (a relay nucleus with projections
from the cerebellum)
12. Premotor Cortex (BA6)
The premotor cortex is located immediately
rostral to M1.
Its primary function is to assist in integration of
sensory and motor information for the
performance of an action (praxis).
Thus it receives input from secondary
somatosensory area (immediately caudal to S1 in
the parietal cortex) and the ventral anterior
thalamic nucleus
13. Broca's area
Motor speech area 44, 45 located in
Pars triangularis and and pars
opercularis
Controls the spoken speech
14. Frontal eye fields (BA8)
The frontal eye fields are located rostral to
premotor cortex.
Their primary function is associated with control
of voluntary eye movements in the contralateral
visual field for processes such as active visual
search.
15. Cingulate Cortex/Supplementary motor
area (BAs 24, 32)
The cingulate cortex is located in the medial
portion of the cortex just superior to the corpus
callosum.
The supplementary motor area is located medial
to the premotor cortex just anterior to M1.
These regions of the brain have functions that are
involved with drive and motivation along with
environmental exploration
18. Primary somatosensory cortex
The primary somatosensory cortex is located in
the postcentral gyrus, and is part of the somatosensory
system
At the primary somatosensory cortex, tactile representation
is orderly arranged (in an inverted fashion) from the toe (at
the top of the cerebral hemisphere) to mouth (at the
bottom). However, some body parts may be controlled by
partially overlapping regions of cortex.
Each cerebral hemisphere of the primary somatosensory
cortex only contains a tactile representation of the opposite
(contralateral) side of the body.
19.
20. Brodmann area 5,7
BA5 is part of the superior parietal lobule and part of the postcentral
gyrus. It is situated immediately posterior to the primary somatosensory
cortex.
It is involved in somatosensory processing,
movement[1][2] and association, and is part of the posterior parietal
cortex
BA 7 Situated posterior to the primary somatosensory
cortex (Brodmann areas 3, 1 and 2), and superior to the occipital lobe,
this region is believed to play a role in visuo-motor coordination
21. Wernicke's area
BA 22 is located in the superior temporal gyrus in the dominant cerebral
hemisphere, which is the left hemisphere in about 95% of right-
handed individuals and 70% of left-handed individuals
24. OCCIPITAL LOBE AREAS
• Brodmann area 17: Known as V1, this region is located in the occipital lobe's
calcarine sulcus, and serves as the brain's primary visual cortex. It aids the
brain to determine location, spatial information, and color data.
Visuopsychic Visual area parastriate and peristriate areas 18, 19 Surround
the striate area .it aids in Correlation of visual impulses with past memory and
recognition of objects seen, and also the depth
26. TEMPORAL LOBE
Auditosensory 41,42 lobe area : lies at Posterior part of superior temporal
gyrus and anterior transverse temporal gyrus
Function : Reception and perception of isolated auditory impressions of
loudness, quality and pitch
Auditopsychic area 22: lies at Rest of the superior temporal gyrus
Function : Correlation of auditory impressions with past memory and
identification (interpretation) of the sounds heard
28. MOTOR AREAS
Speech area: Lesion of Broca's area on the dominant side of hemisphere
causes expressive aphasia. It is characterised by hesitant and distorted speech
with relatively good comprehension.
A lesion involving language areas that is Wernicke's area and Broca's area both
leads to receptive aphasia. In this condition, auditory and visual
comprehension of language that is naming of objects and repetition of a
sentence spoken by the examiner are all defective.
A lesion involving Wernicke's area and superior longitudinal fasciculus or
arcuate fasciculus results in jargon aphasia in which speech is fluent but
unintelligible jargon.
29. Sensory Areas
First somesthetic or general sensory area (areas 3, 1 and 2 of Brodmann).
When this part of cortex is the site of destructive lesion, a crude form of
awareness persists for the sensation of pain, heat and cold on the opposite
side of lesion. There is poor localization of stimulus. There is loss of
discriminative sensations of fine touch, movements and position of part of the
body.
Somesthetic association cortex (superior parietal lobule) areas 5 and 7 of
Brodmann: A lesion in this area leads to defect in understanding the
significance of sensory information, which is called agnosia. A lesion that
destroys a large portion of this association cortex causes tactile agnosia and
astereognosis which are closely related.
30. SPECIAL SENSORY AREAS
Primary visual area 17 lesion of this area, leads to loss of vision in the visual
field of the opposite side-homonymous hemianopia.
Auditory area: Primary auditory areas 41 and 42: A unilateral lesion involving
the auditory area causes diminution in the acuity of hearing in both ears and
the loss is greater in the opposite ear. However, the impairment is slight
because of the bilateral projection to the cortex and the deficit is difficult to
detect by clinical tests.
Auditory association cortex or secondary area22. In lesions of this area,
interpretation of the sounds is lost.
