this ppt talks about the detailed physiology of temporal lobe and explain in detail about the mechanism involved in speech, auditory response and episodic memory. it also talks about the anatomy and functions of the temporal lobe.

1. Temporal lobe
PRESENTED BY ( GROUPII )
RANJANA CHAURASIA
SHAUN ROBBY
DIANA K
DIBYA DHAKAL
TEJAL BANSAL
TEZENDRA KHATTRI
BRUNDA
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MODERATOR
ANANNYA SHARMA MA’AM

2. Introduction:
 One of the four major lobes of the cerebral cortex.
 This brain segment is present only in primates. Among all primates, humans have
the biggest temporal lobes.
 22% of the cerebral cortex belongs to the temporal lobe.
 Most noteworthy, this lobe contains auditory, vestibular, olfactory, linguistic, and
visual functions.
 It is the seat of human para-psychological and psychic abilities.
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3. Anatomy
 Located below the Sylvian Fissure and anterior to the occipital cortex.
 Limited posteriorly by imaginary line drawn in the preoccipital incisure to the
parietals-occipital sulcus.
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There are three convolutions on the upper side of the temporal lobe. Those are the upper, middle,
and lower gyri.
Subcortical Temporal Lobe structure:
 Limbic cortex
 Amygdala
 Hippocampal formation

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 The primary auditory cortex, is located in the depth of the lateral groove (transverse temporal
gyrus cortex).
 The area of the olfactory projection is located in the hippocampal gyrus, especially in its front
section (called the hip). In addition to the fragrant projection zones, there are centres for
flavour recognition.
 The hippocampal formation is positioned on the lobe’s medial side. Its segments include the
subiculum, the parahippocampal gyrus, the hippocampus, white matter, and dentate gyrus.
 Another anatomically important segment of the temporal lobe is the choroid fissure, it
separates the optic tract and the temporal lobe and also separates the midbrain and
hypothalamus from the temporal lobe.
 The relation between the amygdala and the temporal lobe is very important, as the inputs
from the olfactory bulb are sent to amygdala in this way. Likewise, it receives information from
the association cortex in the same way.

6. Lateral Aspect of the Temporal Lobe
Two sulci -
 i)Superior temporal sulcus
 ii)inferior temporal sulcus
Three gyri –
 i)superior temporal gyrus - Area 22
 ii)middle temporal gyrus -Area 21
 iii)inferior temporal gyrus - Area 20
These gyri terminate anteriorly at the temporal pole – Area 38.
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7. The three gyri:
Superior Temporal Gyrus:
 The superior temporal gyrus is
located between the Sylvian and the
upper temporal sulcus
 Involves area 41, 42, 22
 Primary auditory area – Area 41
 On the left side of the brain this area
helps with the generation and
understanding of individual words.
 On the right side of the brain this
area helps tell the difference
between melody, pitch and sound
intensity.
Medial Temporal Gyrus:
 The middle temporal gyrus is
located between the upper and
lower temporal sulcus.
 This region encompasses most of
the lateral temporal cortex
 It plays a part in auditory
processing and language.
 Language function is left
lateralized in most individuals.
 Brodmann Area 21
Inferior Temporal Gyrus:
 The inferior temporal gyrus is
located between the lower
temporal sulcus and the
transverse cerebral fissure.
 Brodmann Area 20
 The region encompasses most of
the ventral temporal cortex, a
region believed to play a part in
high-level visual processing and
recognition memory.
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8. Medial Aspect of the Temporal Lobe
Parts of the medial aspect:
 Amygdaloid complex
 hippocampal gyrus
 dentate gyrus
 inferior temporal lobe
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9. Hippocampus
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It resembles a ‘sea horse’ for which it is named after.
It is divided into 6 different areas
I. Dendate gyrus: dense layer of cells at tip of
hippocampus
II. Cornu ammonis – CA1
III. CA2
IV. CA3
V. CA4
VI. Subiculum – at the base of the hippocampus and
continuous with the entorhinal cortex, which is
part of parahippocampal gyrus.

10. Functions:
 Medial temporal lobe memory system, includes hippocampus and adjacent
cortex, parahippocampal gyrus and perirhinal regions, is involved in storage of
new memories.
 Hippocampus is critical for long-term memory.
 Declarative (explicit) memory – hippocampus, fornix and corpus mammilare
 Non-declarative (implicit) memory – basal ganglia, limbic system, cerebellum.
Cerebral cortex and hippocampus.
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11. Dentate Gyrus
 It’s a part of hippocampal formation
 Input – is from the entorhinal cortex (perforant pathway)
 Dendate gyrus id one of the few regions of the brain where neurogenesis takes
place, which play a role in the formation of new memories.
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12. Amygdaloid complex
 Greek for almond
 Located at the end of the hippocampal formation
 Consists of cortical nucleus and a nuclear part
 Inputs – association areas of visual, auditory and somatosensory cortices are main
inputs to amygdala.
 Outputs – hypothalamus and brainstem autonomic centres and the sympathetic
neurons are the main outputs.
 Functions – emotional learning and memory modulation.
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13. Arterial supply:
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Lateral aspect is perfused mainly by
branches of the Middle Cerebral Artery:
 Anterior temporal artery
 Middle temporal artery
 Temporo-occipital artery

14.  Middle and Inferior temporal gyrus is
 supplied by temporal branches of the
 Posterior Cerebral artery.
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15. Venous drainage:
 The superficial middle cerebral vein drains most of the lateral aspect.
 It follows the Sylvian fissure to end at the cavernous sinus
 A superior anastomotic vein of Trolard connects the superior middle cerebral vein
to the superior sagittal sinus
 An inferior anastomotic vein of Labbe runs over the temporal lobe and connects
the superior middle cerebral vein to the transverse sinus
 A few inferior cerebral veins drain the inferior aspect and anastomose with basal
and middle cerebral veins and drain in to the cavernous, transvers and superior
petrosal sinuses.
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17. physiology
Temporal lobe of cerebral cortex includes three functional areas
 Primary auditory area
 Secondary auditory area or auditopsychic area
 Area for equilibrium.
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18. Primary auditory area
It includes:
 1. Area 41
 2. Area 42
 3. Wernicke area.
 Areas 41 and 42 are situated in anterior transverse gyrus and lateral surface of
superior temporal gyrus. Wernicke area is in upper part of superior temporal
gyrus posterior to areas 41 and 42.
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19. Connections of Primary Auditory Area :
Afferent connections
Primary auditory are receives afferent fibers from:
 1. Medial geniculate body via auditory radiation
 2. Pulvinar of thalamus.
Efferent connections:
This area sends efferent fibers to:
 1. Medial geniculate body
 2. Pulvinar.
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20. SECONDARY AUDITORY AREA
 Secondary auditory area occupies the superior temporal gyrus. It is also called or
auditopsychic area or auditory association area. It includes area 22.
 This area is concerned with interpretation of auditory sensation along with
Wernicke area. It is also concerned with storage of memories of spoken words
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21. AREA FOR EQUILIBRIUM
 Area for equilibrium is in the posterior part of superior temporal gyrus. It is
concerned with the maintenance of equilibrium of the body. Stimulation of this
area causes dizziness, swaying, falling and feeling of rotation.
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22. Major functions:
The temporal lobe contributes in three of the major functions
 Auditory response
 Speech
 Episodic memory
The temporal lobe also plays a role in vision and understanding the visuals.
Predominantly, the vision comes in occipital lobe but the temporal lobe too has a
role to play.
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23. Auditory response:
The main and the primary functions of the temporal lobe is comprehension of
sounds
that is when the sound comes in , and you are constantly aware of it, that is because
of the primary auditory cortex.
but the processing of that sound occurs in Wernicke’s area(auditory association
cortex)
(so, when you hear a sound which is just a noise it is because of the auditory cortex
but wen that sound makes sense to you or you are able to interpret it relating to a
previous experience , that is only because of the Wernicke’s area)
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24. speech
 It can be divided into
 auditory input(hearing and speaking)
 visually received input (seeing and speaking)
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25. auditory input(hearing a sound)
Area no 41(primary auditory cortex)
Information just gets received ,initial comprehensions happens.
Area no 42 (Secondary auditory cortex)
Detailed comprehension of sound, intensity ,
frequency , e can say individual words are recognized
Wernicke’s area (centre for communication)
Makes the complete meaning of the the information
Generates thoughts, Selects words and grammar)
Area no
41
Area
no 42
Wernickes area
(22)
Brocas
area
(44)
Primary motor area(4)
Muscles of speech
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26. Info reaches in Broca’s area
(it is the main motor center for communication)
For speech articulation and its control)
We can also call it the word formation area,
it makes the motor plans and patterns for production of speech.
Stimulation of motor area( Broadman's area 4)
Stimulation of all other supplementary motor areas
(cerebellum, basal ganglia , brain stem, muscles of speech)
Execution of the motor movements (speech production )
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27. Visually received input
Information goes to primary visual cortex (area 17)
(initial comprehension)
Area no 18
Then it proceeds to angular gyrus (this is what is the difference
and what makes seeing and speaking more complex, relatively.
and also is developed later in early life)
Wernicke’s area(area 22)
Assigns meaning to the received information
Broca's area
Rest is same
Area 17
Area 18
Angular
gyrus
Wernicke's
area
Broca's
area
Pri M C
Arcuate fasciculus
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28. Episodic memory
The hippocampal indexing theory
This theory explains that when we have a conscious experience , many different areas
of the neocortex are activated corresponding to different aspects of that experience(
for ex, the visual cortex of visual aspect, the auditory cortex for auditory aspect etc)
When you remember that experience later, similar areas in the neocortex are
activated.
Results in our re- experiencing of that event.
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Input from all parts of
the neocortex in compressed manner enters
Entorhinal cortex
the axons in the entorhinal cortex project to the
dentate gyrus through the performant pathway
The cells in the dentate gyrus then project their
axons(k/a mossy fibers) to CA3
The cells in CA3 project their axons
(a/k/a s Schaffer collaterals) to CA1
The cells in CA1 send their axons to cells in subiculum
The cells in subiculum completes the loop by sending their axons
back in entorhinal cortex

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ENTORHINAL
CORTEX
DENTATE
GYRUS
CA3
CA1
subiculum
INPUT
N
E
O
C
O
R
T
E
X
Mossyfibers
Perforant
pathway

31. Major excitatory neural components of
the hippocampus
Perforant pathway
Forms excitatory connection between
the parahippocampal cortex and the
granule cells of the dentate gyrus.
Mossy fibers
Connect the granule cells of the
dentate gyrus to CA3 pyramidal
cells.
Schaffer collaterals
Connect the CA3 pyramidal cells to
the CA1 pyramidal cells.
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32. Thank you
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