Higher Cortical Functions

1. Higher Cortical Functions
Dr. RUTAYISIRE François Xavier
PGY2
Basic Neurosciences module
University of Rwanda
Supervisor: Dr. MUNYEMANA Paulin

2. Higher Cortical Functions

3. •The higher cortical functions {COGNITIVE FUNCTIONS}
include language, vision, recognizing objects in space
(visuospatial recognition), and awareness…
•The admittedly vague descriptor for the brain regions that
carry out these functions is the association cortex (or
cortices)

4. Association cortex
• Lateral and medial views of the
human brain show the association
cortices in blue. The primary
sensory and motor regions of the
neocortex are shown in yellow.
• Notice that the primary cortices
occupy a relatively small fraction of
the total area of the cortical mantle.
• The remainder of the neocortex—
defined by exclusion as the
association cortices—is the seat of
human cognitive ability.

5. Neocortex
• Most of the cortex that
covers the cerebral
hemispheres is
neocortex, defined as
cortex that has six
cellular layers, or
laminae.
• Each layer comprises
more or less distinctive
populations of cells
based on their different
densities, sizes, shapes,
inputs, and outputs.

6. Based on variations in
the
thickness, cell density,
and other histological
features of the six
neocortical laminae, the
human brain can be
divided into some 50
cytoarchitectonic areas,
typically those
recognized by the
neuroanatomist
Korbinian Brodmann in
his seminal 1909

7. 4 Cortical motor areas
• Primary motor area
• Premotor area
• Motor eye field area
• Broca’s area
For each cortical area, let’s consider
the:
• Site
• Arterial supply
• Function
• Effect of a lesion

8. Primary motor area
• Site: Precentral Gyrus & anterior part of paracentral gyrus
• Arterial supply: upper 1/4th and PCL= ACA
Lower 3/4th= MCA
Representation: Opposite half of the body is upside down
1. Lower third: Head region
2. Leg and foot: Paracentral lobule
• Function:
1. Origin to corticospinal and corticobulbar tracts
2. Initiation of fine of the highly skilled fine movements
• Lesion: Contralateral hemiplegia with five known signs of UMNLs

9. Premotor area
• Site: Anterior to area 4
• Arterial supply: upper 1/4th = ACA
Lower 3/4th= MCA
• Function:
1. Stereotyped movements of muscles through connection with basal
ganglia.
2. Planning and execution of learned motor activity by storing the programs
of motor activity learned by experience such as walking or dancing
• Lesion: Apraxia: difficult performing learned motor activity without
paralysis

10. Motor eye field area
• Site: Posterior part of middle frontal gyrus
• Arterial supply: MCA
• Function: Horizontal movement of the 2 eyes to
the opposite sides
• Lesion: Ipsilateral deviation of the 2 eyes due to
unopposed action of intact area 8

11. Broca’s area #44, 45
• Site: Dominant hemisphere, In the posterior part of IFG
1. Opercular gyrus: area 44
2. Triangular gyrus: area 45
• Arterial supply: MCA
• Function: Coordinates the muscles used for speech (Lips, tongue and larynx) for
speech production
• Lesion : Lesion in Broca's area will cause Motor aphasia;
 Patients can not form words and is unable to express himself.
 Th patient can understand and point at object
 Lesion in the nondominant hemisphere, has no effect

12. Prefrontal cortex: Area 9, 10, 11, 12
Personality center
• Site: Frontal pole
• Arterial supply: ACA, MCA
• Function:
1. Make up of the person’s personality
2. Regulations the depth of the person’s feelings and emotional
behaviors
3. Higher intellectual function such as production of ideas and
judgment.
• Lesion: Loss of personality and patient has no appreciation to any
social behavior.

13. SENSORY areas
1. General sensory area (3, 1, 2)
2. Sensory association area (5, 7, 40)
3. Primary auditory area (41, 42)
4. Auditory association area (22)
5. Primary visual area (17)
6. Visual association area (18, 19)
7. Others: Taste, Olfactory , vestibular

14. General sensory area(3,2,1)
• Site: Postcentral gyrus & posterior part of paracentral lobule
• Arterial supply: Upper 1/4 & PCL: ACA
Lower 3/4: MCA
• Representation: similar to area 4
Opposite half of the body is upside down
1. Lower third head region
2. Leg and foot paracentral lobule
• Function: Receives general sensations from the opposite side of the body &
face.
• Lesion: Contralateral hemianesthesia

15. Somatic sensory association area(5,7,40)
• Site:
1. Superior parietal lobule: # 5 & 7
2. Supramarginal gyrus: # 40
• Arterial supply: ACA & MCA
• Function: Stereognosis, Interpretation of senses perceived in the general sensory
area
• Lesion:
1. Astereognosis: inability to recognize objects by the sense of touch with the
eyes closed.
2. Unliteral neglect: lesion in area 40 with inability to recognize left from right
40
5&7

16. Primary auditory area 41,42
• Site: Middle of the upper surface
of the superior temporal gyrus
• Arterial supply: MCA
• Function: Hearing from the 2
ears. mainly from the opposite
ear
• Lesion: Bilateral diminution of
hearing mainly on the opposite
side.
Auditory Association Area:
Wernicke's Area #22
• Site: posterior part of the
superior temporal gyrus
• Arterial supply: MCA
• Function: recognition of sounds
• Lesion: auditory agnosia &
sensory aphasia, Inability to
understand the spoken
languages.

17. Primary visual area( Area 17)
• Site: Above and below the calcarine sulcus
• Arterial supply: PCA
• Function: receives optic radiations from LGB for perception of light
Representation of the retina: Temporal fibers of the same eye and nasal
fibers of the opposite eye
1. Macula: posterior 1/3rd of the calcarine sulcus
2. Upper retinal fibers: Above calcarine sulcus(Cuneus)
3. Lower retinal fibers: Below calcarine sulcus(Lingual Gyrus)
• Lesion: Contralateral homonymous hemianopsia with macular sparing.

18. Visual association area(18,19,39)
• Site:
1. Area 18 and 19: Above and below area 17
2. Area 39: Angular gyrus
• Arterial supply:
1. Area 18 and 19: PCA
2. Area 39: MCA
• Function:
1. Recognition of what we see
2. Color vision: Inferior association area
3. Angular gyrus: Comprehension of written languages
• Lesion:
1. Visual agnosia: Inability to recognize what we see
2. Loss of color vision: Inferior association area
3. Alexia and agraphia: lesion in angular gyrus

19. Primary olfactory area(Area 34)
• Site: Uncus
• Irritative lesion will cause olfactory hallucinations
Olfactory association area(Area 28)
Site: Anterior part of hippocampal gyrus
Function: discrimination of odors
Face recognition area(Area 37)
Site: posterior part of fusiform gyrus
Function: similar to area 19 and 39
1. Face and body recognition
2. Words recognition
3. Numbers recognition
Lesion: Prosopagnosia(Face blindness)
Inability to recognize familiar faces
They can rely on sounds

20. Language areas
• We have 4 language areas
• 1 Motor speech area( Broca's area 44 and 45)
Lesion: Expressive(Motor) aphasia
• 3 Sensory speech area(22,39,40)
• Wernicke's area 22: understand the spoken languages
• Lesion: sensory aphasia( Inability to understand the spoken /written languages)
• Angular gyrus: Area 39; understand the written languages
• Lesion: Agraphia, alexia
• Supramarginal gyrus( area 40): Understand shape, size & texture and recognition
of the body parts and left side from the right side.

21. Processing of written languages
E.g: Reading from a book
Retina
Primary visual
area
#18,19 for
recognition
Angular Gyrus
to
complehent
written form
Wernickes
area to
complehent
auditory form
Brocas area
through
arcuate
fasciculus to
formulate
words
Area 4
Corticobulbar
tract
VII, X, XII to
lips, laryngx
and tongue

22. Processing of spoken language
Muscles of the lips, larynx and tongue
VII, X, XII
Corticobulbar tracts
Area 4
Broca's area through the arcuate fasciculus to formulate
words
Wernicke's area to comprehend the spoken words
Primary auditory area 41,42
Ear
Answering a question like: What is your name?

23. MMSE

24. References
• Dale Purves book of neuroscience 6th edition
• K.S. Saladin anatomy & physiology: the unity of form and function, 9th
edition
• JAHANGIR MOINI FUNCTIONAL AND CLINICAL NEUROANATOMY A
Guide for Health Care Professionals
• Dejong’s The neurologic examination 7th e d i t i o n