1. Medical Science University of Isfahan, Department of Anatomy
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Medical Science University of Isfahan, Department of Anatomy
Isfahan University of Medical Sciences, Biomedical Sciences Department

2. من لم یعلم التشریح والنجوم فهو عنّین فی معرفت الله
One who do not have the knowledge of Anatomy and Astronomy, will not be able to know God
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Figure 12.2b

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4. Lecture 12 Cerebral hemispheres - Structure - Function
- Related structures
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7. General Arrangement of the Cerebrum:
Cerebral hemispheres:
 derived from the embryological ‘Telencephalon’ (see ‘development’)
 underlying white matter (afferent & efferent fibres)
 deep nuclear masses = basal ganglia
The two cerebral hemispheres are:
 Separated by the great longitudinal fissure
 Joined by the corpus callosum (nerve fibre system, see later)
divided into 4 lobes:
Frontal
Parietal
Temporal
Occipital
additional structure:
Insula (buried deep below the lateral fissure)
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8. Development of Sulci
Sulci appear at predictable points in fetal development with the most prominent sulci (e.g., Sylvian fissure) appearing first.
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Source: Ono, 1990

9. Squirrel monky Cat Rhesus monky Dog Chimpanzee Man
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10. Cerebral hemispheres Each of them has: 3 poles : 3 Borders :
Frontal, Occipital, Temporal
3 Borders :
Superior, inferomedial & inferolateral
3 Surfaces :
Superolateral, medial & inferior
Inferior surface : orbital & tentorial
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11. Each surface included some suci & gyri
Sulcus A depression or groove in the surface of the cerebrum that helps increase surface area of the cerebrum.
Gyrus An elevated ridge that projects upwards between the sulci of the cerebrum and also helps increase surface area of the cerebrum.
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12. Defining the lobes central (rolandic) sulcus frontal lobe
parietal lobe
occipital
lobe
temporal lobe
sylvyan (lateral) sulcus
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18. Sulci of lateral view Lateral sucus: Central sulcus :
Anterior horizontal
Anterior ascending
Posterior
Central sulcus :
Superior frontal &
Inferior frontal sulci
Superior & middle temproal gyri
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21. Sulci of medial view Cingulate sulcus Parieto – occipital sulcus
Calcarine sulcus
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23. Sulci of inferior view Tentorial portion: Orbital portion
Collateral sulcus
Fronto - occipital sulcus
Orbital portion
Oribital sulci
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25. 6 1 4 8 Supramarginal 10 3 Angular 2 44 41 17 45 42
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26. 19 18 17 18 19
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27. Main sulci are formed early in development Fissures are really deep sulci
Typically discontinuous sulci:
Superior frontal sulcus
Inferior frontal sulcus
Postcentral sulcus
Intraparietal sulcus
Superior temporal sulcus
Inferior temporal sulcus
Cingulate sulcus
Precentral sulcus
Typically continuous sulci:
Interhemispheric fissure
Sylvian fissure
Parieto-occipital fissure
Collateral sulcus
Central sulcus
Calcarine Sulcus
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Medical Science University of Isfahan, Department of Anatomy
Source: Ono, 1990

28. Function of cerebral cortex
Cerebral Cortex is:
the outer layer of the cerebrum that consists of gray matter which deals with conscious motor action, sensation, memory, communication, reasoning, emotions, intelligence.
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29. Functions of Cerebral lobes
Frontal Lobe controls conscious muscle action, planning for movements, motor memory, voluntary eye movements.
Parietal Lobe Controls conscious interpretation of sensation from muscles, tongue and cutaneous areas.
Temporal Lobe --- conscious interpretation of auditory and olfactory sensations. Memory of sounds and smells.
Occipital Lobe the most posterior lobe of the cerebrum which deals with conscious seeing, eye focus and integrating visual memory with other sensations.
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30. Insula (Island of Reil) (‘fifth lobe’)
Covered by parietal and temporal lobes, not visible from the outside within the lateral fissure
It is a component of a functional lobe which is called limbic lobe
Limbic lobe is related to emotional and autonomic response to external stimuli
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31. Cerebral cortex
Sensory Area of the Cerebral Cortex -- Located in areas posterior to the central sulcus. Receives and interprets conscious sensory impulses. The postcentral gyrus of the parietal lobe is a key ridge of gray matter that allows a person to judge the source of sensory stimuli.
Motor Area of the Cerebral Cortex --- Located in areas anterior to the central sulcus. Plans and initiates impulses for conscious motor movements. The precentral gyrus of the frontal lobe is an another key ridge of gray matter that allows a person to operate specific areas of the body.
Associatiopn Area of Cerebral cortex
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33. Cytoarchitecture of cerebral cortex
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34. Cytostructure of cerebral cortex
1 – Molecular layer
2 – External granular layer
3 – External pyramidal layer
4 - Internal granular layer
5 – Internal pyramidal layer
6 – Multiform layer
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36. Cytoarichitecture of cerebral cortex based on Brodmann divisioions
Brodmann area
Location
Function 17
Banks of cal.sul
Primary visual c
18, 19
Medial aspect of occipital lobe
Secondary visual cortex
3,1,2
Postcentral gyr.
primary somato. 4
Precentral gyr.
Primary motor 6
Sup&middle f.g.
Premotore cort.
44,45
Inf. front. gyirus
Speech
41,42
Sup. tem .gyr.
Auditory cortex
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37. Primary Motor Cortex
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38. Somatic Sensory Cortex
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39. 6 1 4 8 Supramarginal 10 3 Angular 2 22 44 41 42 17 45
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43. Right vs. Left hemisphere
Lateralisation: asymmetrical distribution of function, emerges during fetal development
Example: Hand preferences
General distribution of functions:
Right hemisphere:
Non-verbal perceptual tasks, visual & spatial perception
Left hemisphere:
Language & analytic functions
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44. *
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45. Ventricles Hollow spaces in the brain which store cerebral spinal fluid ( CSF ) for support, protection and circulation of extracellular fluid (ECF).
Cerebral Spinal Fluid ( CSF ) - A specialized extracellular fluid produced by choroid plexus which bathes, supports and protects the interior of the brain and spinal cord.
Choroid Plexus A cluster of specialized capillaries enclosed by specialized cells that line the brain ventricles. These circulatory bodies produce cerebral spinal fluid ( CSF ).
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47. Four Ventricles Lined by ependymal cells CSF filled chambers
Communicating with central canal of spinal cord
Lined by ependymal cells
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50. Function of Brain Structures Continued
Sensory Area of the Cerebral Cortex -- Located in areas posterior to the central sulcus. Receives and interprets conscious sensory impulses. The postcentral gyrus of the parietal lobe is a key ridge of gray matter that allows a person to judge the source of sensory stimuli.
Motor Area of the Cerebral Cortex --- Located in areas anterior to the central sulcus. Plans and initiates impulses for conscious motor movements. The precentral gyrus of the frontal lobe is a another key ridge of gray matter that allows a person to operate specific areas of the body.
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51. Brain Structure Functions Continued
Association Areas Regions of the cerebral cortex that analyze, recognize and act on sensory input and communicate with the motor areas. Examples include the visual and auditory association areas.
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53. The localisation of language functions in the human brain
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54. Speech Wernicke’s area: Sensory speech Broca’s area: Motor speech
Speech area normally in left cerebral cortex
Wernicke’s area: Sensory speech
Broca’s area: Motor speech
Aphasia: Absent or defective speech or language comprehension
1) Broca’s aphasia (expressive aphasia, motor aphasia)
2) Wernicke’s aphasia (no comprehension & failure to convey meaning
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56. How to speak in response to seeing a word or hearing it.
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Figure 9-23: Cerebral processing of spoken and visual language

57. Brain white mater Association fibers: Commissural fibers:
Short association fasciculus
Long association:
Superior long association fasciculus
Inferior long association fascculus
Uncinate (frontotemporal) fasciculus
Commissural fibers:
Corpus callosum
Fornix
Anterior commisure
Posterior commisure
Projection fibers
Ascending
Descending
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58. Cortical white matter: links with other brain structures
1) Projection fibres: between cortex and subcortical structures
Fibres form: corona radiata (fan-like arrangement),
converge and concentrate to form the internal capsule
2) Commissural fibres: inter-hemispheric connection
Main system: Corpus callosum (CC)
Anterior commissure: connects temporal fields
Hippocampal commissure (Fornix)
3) Association fibres: intra-cortical connections
short, U-fibres arching beneath adjacent sulci
long, travel through white matter
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59. Red: projection fibres Green: commissural fibres
Blue: association fibres
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