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The Telencephalon
Liu jiao
Binzhou Medical University
Department Of Anatomy
External feature
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The telencephalon consists of
right and left cerebral hemisphere,
partially separated by cerebral
longitudinal fissure.
The cerebral transverse fissure
intervenes between the
hemispheres and the cerebellum
Each hemisphere has three
surfaces: superolateral, medial
and inferior
Three principal sulci
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Central sulcus
Lateral sulcus
Parietooccipital sulcus
Central sulcus
Parietooccipital sulcus
Lateral sulcus
Five lobes
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Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
Insular lobe
Parietal lobe
Insular lobe
Sulci and gyri of Superolateral surface
Frontal lobe:
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Precentral sulcus
Superior frontal sulcus
Inferior frontal sulcus
Precentral gyrus
Superior frontal gyrus
Middle frontal gyrus
Inferior frontal gyrus
Sulci and gyri of Superolateral surface
Precentral gyrus
Precentral sulcus
Superior frontal sulcus
Inferior frontal sulcus
Superior,
middle
and inferioe
frontal
gyri
Parietal lobe:
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Postcentral sulcus
Postcentral gyrus
Intraparietal sulcus
Superior parietal lobule
Inferior parietal lobule
Supramarginal gyrus
Angular gyrus
Sulci and gyri of Superolateral surface
Postcentral gyrus
Postcentral sulcus
Superior parietal lobule
Intraparietal sulcus
Supramarginal
gyrus
Angular gyrus
Temporal lobe:
 Superior temporal sulcus
 Inferior temporal sulcus
 Superior temporal gyrus
 Middle temporal gyrus
 Inferior temporal gyrus
 Transverse temporal gyri
Sulci and gyri of Superolateral surface
Superior temporal sulcus
Superior temporal gyrus
Inferior temporal sulcus
Middle temporal gyrus
Inferior temporal gyrus
Transverse temporal gyri
Sulci and gyri of Superolateral surface
Precentral gyrus
Precentral sulcus
Postcentral gyrus
Postcentral sulcus
Superior frontal sulcus
Superior parietal lobule
Inferior frontal sulcus
Superior,
middle
and inferioe
frontal
gyri
Supramarginal
gyrus
Angular gyrus
Superior temporal sulcus
Superior temporal gyrus
Inferior temporal sulcus
Middle temporal gyrus
Inferior temporal gyrus
Sulci and gyri of medial surface
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Corpus callosum
Callosal sulcus
Cingulate gyrus
Cingulate sulcus
Marginal ramus
Paracentral lobule
Calcarine sulcus
Cuneus
Lingual gyrus
Sulci and gyri of medial surface
Corpus callosum
Callosal sulcus
cingulate gyrus
Paracentral lobule
Marginal ramus
Parietooccipital sulcus
Cingulate sulcus
Cuneus
Calcarine sulcus
Lingual gyrus
Sulci and gyri of inferior surface
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Olfactory bulb
Olfactory tract
Olfactory trigone
Anterior perforated substance
Collateral sulcus
Occipitotemporal sulcus
Medial occipitotemporal gyrus
Lateral occipitotemporal gyrus
Hippocampal sulcus
Parahippocampal gyrus
Uncus
Hippocampus
Hippocampal formation
Dentate gyrus
Inferior surface
Olfactory bulb
Olfactory tract
Uncus
Occipitotemporal sulcus
Parahippocampal
gyrus
Medial and lateral
occipitotemporal
gyri
Collateral sulcus
Olfactory trigone
Anterior perforated
substance
Hippocampus
Dentate gyrus
Hippocampal
formation
Histology of the cerebral cortex
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Archicortex
(hippocampal
formation )
Paleocortex
(rhinencephalon )
Neocortex
(most of cerebral cortex)
3 cell layers
6 cell layers
Functional location of
cerebral cortex
First somatic motor area
Position: located in precentral gyrus and anterior
portion of paracentral lobule
First somatic motor area
Characters
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Representation is inverted,
but head and face are
upright
A body part is represented
by a cortical area
proportional to its use
rather than its size
Receiving fibers from postcentral
gyrus, VA, VL and VPL, sending
out fibers to form pyramidal tract,
controlling voluntary movements
First somatic sensory area
Position－lies in
postcentral gyrus and
posterior portion of
paracentral lobule
First somatic sensory area
Characters
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Sensory representation,
like motor area, is
crossed and inverted
Receiving and interpret
sensation from opposite
side of body
Auditory area
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Located in transverse
temporal gyri
Receive auditory
information from both
ears
Visual area
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Lie on either side of
calcarine sulcus in medial
surface of occipital lobe
Visual cortex of one
hemisphere receives
impression from temporal
part of retina of same side
and nasal part of opposite
side
Lesions of visual cortex
produce contralateral
homonymous visual field
defections
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Vestibular area: located in front of superior temporal gyrus
Olfactory area : located near the uncus
Taste area : located in the dorsal wall of the lateral sulcus
Language area
It is dominant in left hemisphere in
right-handed person
 Motor speech area
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Writing area
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Located in posterior portion of
middle frontal gyrus
Damage: agraphia
Auditory speech area
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Located in posterior portion of
inferior frontal gyrus
Damage: motor aphasia
Located in posterior portion of
superior temporal gyrus
Lesion: sensory aphasia
Visual speech area
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Located in angular gyrus
Lesion: alexia
Internal structures
Lateral ventricle
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Position:
located in cerebral hemispheres
Four parts
 Central part: lies in parietal lobe
 Anterior horn: extends into frontal lobe
 Posterior horn extend into occipital lobe
 Inferior horn: extend into temporal lobe
Communication
lateral ventricle → interventricular foramen → third ventricle
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Basal nuclei
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Corpus striatum
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Lentiform nucleus
Caudate nucleus
Claustrum
Amygdaloid body
Globus pallidus －paleostriatum
putamen
Neostriatum
White matter
Association fibers
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Run between gyri within the
same hemisphere
Cerebral arcuate fibers
Superior
longitudinal fasciculi
Inferior
longitudinal fasciculi
Uncinate fasciculus
Cingulum
Commissural fibers
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－ run between left and
right hemisphere
Corpus callosum: rostrum,
genu, trunk, splenium
Anterior commissure
Fornix and commissure of
fornix
Projection fibers: connect
cortex with lower part of brain
and spinal cord and they
include both ascending and
descending fibers
Internal capsule
 Position: a thick lamina of
white matter lying between
caudate nucleus, thalamus
and lentiform nucleus
Three parts
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Anterior limb of internal capsule
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Genu of internal capsule
Is angle at which anterior and
posterior limbs meet
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Lies between caudate nucleus and
lentiform nucleus
Containing frontopontine tract and
anterior thalamic radiation
Containing corticonuclear tract
Posterior limb of internal capsule
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Lies between thalamus and lentiform
nucleus
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Contain corticospinal tract,
corticorubral tract, central
thalamic radiation, parietooccipito-temporo-pontine tract,
acoustic radiation and optic
radiation
Anterior thalamic radiation
Head of caudate nucleus
Frontopontine tract
Corticonuclear tract
Corticospinal tract
Dorsal thalamus
Central thalamic
radiation
Lentiform nucleus
Corticorubral tract
Parieto-occipitotemporo-pontine tract
Acoustic radiation
Medial geniculate body
Optic radiation
Lateral geniculate body
Internal capsule
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The lesion of internal capsule results in:
1)voluntary motor paralysis on the opposite
side of the body
2)loss of general sensation on the opposite
side of the body
3)blindness in the opposite visual field
Limbic system
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Composition
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Limbic lobe: includes septal area, cingulated gyrus, parahippocampal
gyrus, hippocampus, dentate gyrus, temporal pole, anterior part of
insular lobe and so on
Associated subcortical nuclei: amygdaloid body, septal nuclei,
hypothalamus, epithalamus, anterior nucleus group of thalamus,
tegmentum of midbrain
Function: concerned with visceral activities, olfaction, emotion
and memory, so this system is called ‘visceral brain’