TEMPORAL LOBE ANATOMY,FUNCTION DISORDER,MRI FINDING

1. TEMPORAL LOBE

2. •H.H.
–40 years old, successful lawyer
–Left wife of 15 years to join a religious group
–Experienced a seizure and a left temporal lobe
tumor was found
–Tumor removed and H.H. was able to return to his
job
–Left with word-finding difficulties

3. • ANATOMY(parts)
• FUNCTIONAL AREAS
• LOOPS & PATHWAYS
• FUNCTIONS
• DISORDERS
3

4. ANATOMY OF TEMPORAL LOBE

5. Directionally, the temporal lobes are anterior to the
occipital lobes, inferior to the frontal lobes and parietal
lobes, and lateral to the Fissure of Sylvius, also known
the lateral sulcus
5

6. Occurs only in primates and is largest in man
Approximately 17% of the volume of cerebral cortex
16% in the right and 17% in the left hemisphere
Temporal cortex includes auditory, olfactory,
vestibular, and visual senses ,prception of spoken and
written language
Addition to cortex, its contains white matter, part of
the lateral ventricle, the tail of the caudate nucleus,
the stria terminalis, the hippocampal formation, and
the amygdala

7. • SUPERIOR AND INFERIOR TEMPORAL SULCI
DIVIDE TEMPORAL LOBE INTO 3 LOBES
• SUPERIOR TEMPORAL LOBE
• MIDDLE TEMPORAL LOBE
• INFERIOR TEMPORAL LOBE
7

9. Involves areas 41,42,22
Primary auditory area (area 41)
On the left side of the brain this area helps with
generation and understanding of individual words.
On the right side of the brain it helps tell the difference
between melody, pitch, and sound intensity
9

10. The region encompasses most of the lateral temporal
cortex, a region believed to play a part in auditory
processing and language
Language function is left lateralized in most individuals
Brodmann area 21
10

11. Its corresponds to the inferior temporal gyrus.
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
11

12. Auditory areas
Brodmann’s areas 41,42,
and 22
Ventral Stream of Visual
Information -Inferotemporal
cortex or TE, Brodmann’s
areas 20, 21,37, and 38

13. Relations of the temporal lobe coronal section passing through the temporal pole,
anterior to the amygdala, hippocampus, and temporal horn

14. Relations of the temporal lobe coronal section passing through the amygdala and the
head of the hippocampus

15. Relations of the temporal lobe, horizontal section in the plane of the
pituitary gland

16. The hippocampus is a scrolled structure located in the medial temporal
lobe
The hippocampus can be divided into at least five different areas.
The dentate gyrus is the dense dark layer of cells at the "tip" of the
hippocampus. Areas CA3 and CA1 are more diffuse; the small CA2 is
hard to distinguish between them. (CA stands for cornu ammonis,
from its ram's horn shape.)
The subiculum sits at the base of the hippocampus, and is continuous
with entorhinal cortex, which is part of the parahippocampal gyrus.

17. Dentate gyrus represents the free edge of the pallium and associated
white matter, the alveus, fimbria, and fornix.
The cortex adjacent to the hippocampus is known as the entorhinal area,
it present along the whole length of the parahippocampal gyrus
The hippocampal formation has indirect afferent connections from the
whole of the cerebral cortex, funneled through the adjacent temporal
cortex and the subiculum

19. 19

20. (1) inputs from the entorhinal region, which include the perforant and alvear
pathways; (2) internal circuitry, which includes the connections of the mossy
fibers and Schaffer collaterals; and (3) efferent projections of the hippocampal
formation through the fimbria-fornix system of fibers. CA1-CA4 denote the

21. The hippocampus is
vulnerable to ischemia,
which is any obstruction of
blood flow or oxygen
deprivation, Alzheimer's
disease, and epilepsy.
These diseases selectively
attack CA1, which
effectively cuts through the
hippocampal circuit
21

23. Amygdala
Amygdala located in the medial part of the temporal pole,
anterior to and partly overlapping the hippocampal head
Its receives fibres of the olfactory tract
The ambient and semilunar gyri consist of periamygdaloid
cortex receives fibres from the olfactory tract
The larger lateral part of the amygdala, like the hippocampal
formation, receives direct and indirect input from most of the
cerebral cortex

24. Inputs: The association areas of visual, auditory, and somato
Sensory cortices are the main inputs to the amygdala
Outputs: The main outputs of the amygdala are to the
Hypothalamus and brainstem autonomic centers, including
the
vagal nuclei and the sympathetic neurons
The amygdala is also involved with mood and the conscious
emotional response to an event
The amygdala is also extensively interconnected with frontal
cortex, medio dorsal thalamus, and the medial striatum

25. The deep group, which includes the
lateral, basal, accessory basal
nucleic
Func: collects input from sensory
cortex.
The more dorsal group, which
includes the central & medial
nuclei
Func: receives projections from the
deep group and sends the signal
out
to autonomic centers.
25

26. The amygdala is the heart of the emotional system.
It
processes and interprets all sensory data
It modulates the flow of emotional information
between
the cerebral cortex and the hypothalamus, and in
doing
that, it modulates autonomic, endocrine, and
affective
responses
Lesions in amygdala lead to-- agitation, irritability,
26

27. Kluver-Bucy syndrome results due to a bilateral destruction of
the amygdaloid body and inferior temporal cortex
It is characterized by
Visual agnosia
Placidity
Hypermetamorphosis
Hyperorality
Hypersexuality
causes: cerebral trauma; infections including herpes and
other encephalitides; Alzheimer's disease and other dementias,
Niemann-Pick disease and cerebrovascular disease

28. White Matter
Subcortical white matter comprises three populations of axons
Association fibres connect cortical areas within the same cerebral
hemisphere
largest bundle is the arcuate fasciculus
between frontal cortex, including Broca’s expressive speech area, and
Wernicke’s receptive language area in the posterior part of the superior
temporal gyrus.
The condition of conduction aphasia is traditionally attributed to a
destructive lesion that interrupts the arcuate fasciculus
Another frontotemporal association bundle is the uncinate fasciculus
hook like shape
Visual association cortex extends from the occipital lobe to the middle
and inferior temporal and fusiform gyri

29. Commissural fibres connect mainly but not exclusively symmetrical
cortical areas
Largest group of commissural fibres is the corpus callosum
Projection fibres connect cortical areas with subcortical nuclei of grey
matter
Its afferent to the temporal cortex include medial geniculate body to the
primary auditory area
Connected with the amygdala, hypothalamus, hippocampal formation,
and parahippocampal gyrus
Thalamocortical pathway that passes through the temporal lobe is
Meyer’s loop of the geniculocalcarine tract
This loop carries signals derived from the upper quadrants of the
contralateral visual fields to the corresponding primary visual cortex of
the anterior half of the inferior bank of the calcarine sulcus

31. AUDITORY – primary & Association
OLFACTORY - primary & Association
VISUAL (Recognition & association)
MEMORY
EMOTIONAL & SOCIAL
Link past and present sensory and emotional
experiences into a continuous self

32. LANGUAGE AREAS
Wernicke's area is found in posterior temporal lobe of one
hemisphere (usually the left),called the "speech area, " Wernicke's
area surrounds& encompasses part of the auditory association
Area
AFFECTIVE LANGUAGE AREAS
Involved in the nonverbal emotional components ,present non dominant
hemisphere opposite Brocas's and Wernickes's areas
These "mirror images" allow tone of our voice and our gestures to
express our emotions when we speak, and permit us to comprehend
the emotional content of what we hear
Lesions to this cause aprosodia, in which speech is flat and emotionsess,
lacking the intonations that modify the meaning of our spoken words

33. PRIMARY AUDITORY AREA (area 41)
Essential to detect changes in frequency , & to know the
direction from which sounds originate.
AUDITORY ASSOCIATION AREA (area 42)
HIGHER AUDITORY ASSOCIATION AREA (area 22)
33

34. Processing of our recognition of
objects occurs in a path on the
lower, dorsal stream in the
temporal lobe; here you find
areas sensitive to faces vs.
objects,
Area MT (right) performs
processing on motion. Subjects
without an area MT describe
seeing motion as discontinuous
pictures – eg. having to rely on
sound before crossing a street
34

35. The rightmost green spots are
the location in cortex where
smell is processed
35

36. The sensation of taste is
processed in insular
cortex
36

37. connections of the Temporal
Lobes
Five main types:
Hierarchical sensory pathway
Dorsal auditory pathway
Polymodal pathway
Medial (mesial) temporal pathway
Frontal lobe projection

38. Hierarchical sensory pathway
connections from
primary(sensory neuron) and secondary
auditory
and visual cortical
through the lateral temporal cortex
terminate in the temporal pole

40. visual travels inferior temporal gyrus
auditory travels e suprior temporal gyrus
Major destinations:
amygdala and hippocampus
This results in the integration of information into:
memory, retrieval of stored information, emotional
tone
Ultimate effect
stimulus recognition
The familiar conscious experience of knowing,
assimilating, and feeling

41. Dorsal auditory pathway
Forms important functional connections with the
posterior parietal cortex
Enables location of sounds in space
Promotes orienting and initiation of movements
relative to sound location

43. Polymodal Pathway
connections emerging from the auditory and visual
hierarchical pathways
Directed towards the neurons enfolded within the
superior temporal sulcus
Polymodal nature of neurons
Assigns stimuli to specific category of classes,
linked to and can be retrieved by memory

45. Medial Temporal Projection

46. Medial Temporal Projection
Projections from auditory and visual areas into the
limbic regions
E.g., amygdala and hippocampus
Directions of projections
Peripheral cortex entorhinalcortex
amygdala/hippocampus
Perforant pathway
forms the main projection to the hippocampus
Damage in this region severely affects memory
formation

47. Medial Temporal Projection

48. Frontal-lobe Projection
Neurons from the temporal lobe have
strong connections with the frontal lobe
Posterior temporal cortex
Projects to the dorsolateral prefrontal
cortex
anterior temporal cortex
Projects to the orbital frontal cortex
Damage leads to terrible life decisions

49. Frontal-lobe Projection

50. Frontal-lobe Projection

51. The prefrontal cortex (PFC) divided into anterior (APFC, Brodmann
area (BA) 10), dorsolateral (DLPFC, BA 46 and 9), ventrolateral
(VLPFC, BA 44, 45 and 47) and medial (MPFC, BA 25 and 32) regions
BAs 11, 12 and 14 are commonly referred to as orbitofrontal cortex
The medial temporal lobe comprises the hippocampus and amygdala, as
well as the entorhinal, perirhinal and parahippocampal neocortical
regions.
There are large cortico-cortical direct reciprocal connections between the
PFC and the medial temporal lobe, passing through the uncinate fascicle,
anterior temporal stem and anterior corpus callosum.
The orbitofrontal and dorsolateral cortices have strong reciprocal
connections with the perirhinal and entorhinal cortices
Unidirectional projections exist from the CA1 field to the caudal region
of MPFC
The subicular complex and neocortical medial temporal regions have
reciprocal connections with caudal MPFC

52. Arterial Blood Supply and Venous Drainage
The temporal lobe receives blood from both the carotid and the
vertebrobasilar systems.
Anterior choroidal artery are the anterior end of the parahippocampal
gyrus, the uncus, the amygdala, and the choroid plexus in the temporal
horn of the lateral ventricle
Middle cerebral artery giving off branches that supply the cortex of
the superior and middle temporal gyri and the temporal pole.
Posterior cerebral artery gives off two to four temporal branches,
before it divides into the calcarine and parieto-occipital arteries, which
supply the occipital lobe.
The temporal branches of the posterior cerebral artery supply the
inferior surface of most of the temporal lobe, but not the temporal
pole.

53. The venous drainage of the temporal cortex

54. Venous drainage
Temporal cortex and white matter into the superficial middle
cerebral vein,in the cistern of the lateral sulcus and inferior
anastomotic vein (vein of Labbé)
Interior of the lobe, including amygdala, hippocampus, and
fornix, flows into the posterior choroidal vein.
The left and right internal cerebral veins joined by the basal
veins and unite to form the great cerebral vein, a midline structure
that continues into the straight sinus. The basal vein (vein of
Rosenthal), which carries blood from the cortex and the interior
of the frontal lobe, traverses the subarachnoid space in the
cisterna ambiens, medial to the temporal lobe.

55. Venous drainage

56. Venous drainage

57. Processing auditory input
◦ sends ventral and dorsal streams (object identification and
for movement planning)
Visual object recognition
◦ Ventral visual stream
Biological motion perception
◦ Superior Temporal Sulcus
Long-term storage of information
◦ Memory (limbic system, hippocampus)

58. Temporal Lobe Function
Sensory Processes
Identification and Categorization of Stimuli
Cross-Modal Matching
Process of matching visual and auditory
information
Affective Responses
Emotional response is associated with a particular
stimulus
Spatial Navigation
Hippocampus – Spatial Memory

59. Faces
Special face processing
pathway

60. Asymmetry of Temporal Lobe Function
Left temporal lobe
Verbal memory
Speech processing
Right temporal lobe
Nonverbal memory
Musical processing
Facial processing

61. DISORDERS OF TEMPORAL LOBE

62. Symptoms of Temporal-Lobe Lesions

63. Disturbance of auditory sensation and perception
Disturbance of selective attention of auditory and visual input
Disorders of visual perception
Impaired organization and categorization of verbal material
Disturbance of language comprehension
Impaired long-term memory
Altered personality and affective behaviour
Altered sexual behaviour

64. Disorders of auditory perception:
Lesions of the left superior temporal gyrus produce problems of
speech perception with difficulty in discriminating speech and the
temporal order of sounds is impaired
Lesions of the right superior temporal gyrus can produce disorders of
perception of music with inability to discriminate melodies and produce
prosody
The inferior temporal cortex is responsible for visual perception and
lesions produce inability to recognise faces, called prosopagnosia.
There may be disturbance of visual and auditory input selection. This
presents as impairment of short term memory, also called working
memory and judgement about the recency of events.

65. Disorders of memory
The medial and inferior temporal cortex and hippocampus are
responsible for memory.
There is complete anterograde amnesia following bilateral removal of
medial temporal lobes, including hippocampus & amygdala.
The left side is responsible for verbal material and the right for non-verbal
memory such as faces, tunes and drawings.

66. • Temporal lobe personality. There is egocentricity, pedantic
speech, perseveration of speech, paranoia, religious
preoccupations and a tendency to aggressive outbursts,
especially after right temporal lobectomy
• temporal lobe lesions can present with visual field defects in
the form of superior quadrant loss, sometimes called the "pie
in the sky defect"
• Stroke normally reduces libido but temporal lobe lesions can
increase it

67. • Any disturbance in the comprehension or expression of language
caused by a brain lesion.
• NONFLUENT APHASIA, i.e. in lesion to Broca's area results in
slow speech, difficulty in choosing words, or use of words that
only approximate the correct word.e.g., a person may say "tssair"
when asked to identify a picture of a chair.
• A lesion to Wernicke's area may result in FLUENT APHASIA, in
which a person speaks normally, and sometimes excessively, but
uses jargon and invented words, that make little sense (e.g.,
"choss" for chair). The person also fails to comprehend written
and spoken words.
67

68. Middle cerebral artery in farct:
Aphasia or non-dominant hemisphere findings depending on
the side.“Partial” middle cerebral artery syndromes, almost
always of embolic origin, may include a) sensorimotor paresis
with little aphasia b) conduction aphasia c) Wernicke’s aphasia
without hemiparesis
Wernicke's aphasia, caused by occlusion of the lower division
of the MCA bifurcation or one of its branches
The infarct responsible for a classic Wernicke's aphasia
includes the dominant posterior temporal, inferior parietal, and
lateral temporo-occipital regions
Posterior cerebral artery syndrome:
Recent memory loss may be present (involvement of
hippocampus)
68

87. Bilateral temporal lobe hyperintensity
Infective diseases (herpes simplex virus, congenital
cytomegalovirus infection)
Epileptic syndrome (mesial temporal sclerosis)
Neurodegenerative disorders (Alzheimer's disease,
frontotemporal dementia, Type 1 myotonic dystrophy)
Neoplastic conditions (gliomatosis cerebri)
Metabolic disorders (mitochondrial encephalopathy, lactic
acidosis and stroke-like episodes, Wilson's disease,
hyperammonemia) Dysmyelinating disease
(megalencephalic leukoencephalopathy
with subcortical cysts)
Vascular (cerebral autosomal dominant arteriopathy with
subcortical infarcts and leukoencephalopathy)
Paraneoplastic (limbic encephalitis) disorders

88. Diagnosis (n) Percentage of total cases (n=65) Age or age range (years) Sex distribution
Infective diseases
Herpes encephalitis (15) 23 34–55 10M, 5F
Congenital CMV infection (2) 3 8–11 1M, 1F
Epileptic syndrome
Mesial temporal sclerosis (10) 15.3 8–27 6M, 4F
Neurodegenerative
Alzheimer's disease (7) 10.7 58–65 5M, 2F
Frontotemporal dementia (2) 3 61–64 2F
Myotonic dystrophy (1) 1.5 27 1M
Neoplastic
Gliomatosis cerebri (9) 13.8 33–64 6M, 3F
Metabolic
MELAS (7) 10.7 10–22 5M, 2F
Wilson's disease (1) 1.5 10 1M
Hyperammonemia (1) 1.5 61 1F
Dysmyelinating disease
MLC (6) 9.2 6–20 5M, 1F
Vascular
CADASIL (2) 3 31–35 1M, 1F
Paraneoplastic disorder
Limbic encephalitis (2) 3 25–32 2M
CADASIL, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy;
CMV, cytomegalovirus; F, female; M, male; MELAS, mitochondrial encephalopathy, lactic acidosis and
stroke-like episodes; MLC, megalencephalic leukoencephalopathy with subcortical cysts.

89. The clinical features, location and distribution of temporal lobe
hyperintensity, additional and advanced MRI findings with relevant
laboratory results
↓, decreased; ↑, elevated; −, negative; +, positive; A, anterior;
CADASIL, cerebral autosomal dominant arteriopathy with subcortical
infarcts and leukoencephalopathy; Cho, choline; CMV,
cytomegalovirus; CPS, complex partial seizure; CSF, cerebrospinal
fluid; DWI, diffusion-weighted imaging; EC, external capsule; EEG,
electroencephalogram; Gd, gadolinium; GM, grey matter; HSV, herpes
simplex virus; L, lateral; Lac, lactate; LOC, loss of consciousness; M,
medial; MELAS, mitochondrial encephalopathy, lactic acidosis and
stroke-like episodes; ML, myoinositol; MLC, megalencephalic
leukoencephalopathy with subcortical cysts; MRS, MR spectroscopy;
NA, not applicable; NAA, N-acetylaspartate; ND, not done; P,
posterior; R, restriction; S. no., serial number; SWI, susceptibility-weighted
imaging; WM, white matter; VR, Virchow–Robin spaces.

90. Bilateral temporal lobe hyperintensity Advanced MRI findings
S.
Clinical
Diagnosis
no.
features
Lobe GM WM Additional MRI findings DWI
SW
I
MRS
Gd-enhancement
Laboratory result
1
Herpes
encephalitis
Fever,
seizure,
altered
sensorium
A, M + −
Orbital gyri involvement,
gyriform haemorrhages
R + ND Gyriform
HSV antibodies in
CSF
2
Mesial
temporal
sclerosis
Complex
partial
seizure
M + +
Hippocampal, mamillary
body, fornix and collateral
WM atrophy
− − ND ND
Temporal lobe
localisation on EEG
3
Gliomatosis
cerebri
Headache,
recurrent
seizures
A, M + +
Expansion of
parenchyma, multilobar
involvement
− − ↑ML
Absent /
patchy
Non-contributory
4 MELAS
Episodes of
LOC, seizure
P, M + +
Fleeting hyperintensity,
basal ganglia involvement
R − ↑lac Patchy
↑Serum and CSF
lactate
5
Alzheimer's
disease
Personality
changes,
memory loss
A, M − +
Hippocampal atrophy,
enlarged
parahippocampal fissures
− − ↑ML − Non-contributory
6 MLC
Development
al delay,
seizure
Whole − +
Temporal lobe cysts,
subcorticalWM, external
capsule
− −
↓NAA
↑cho
− Non-contributory
7
Congenital
CMV
Seizure P − +
Periventricular cysts,
pachygyria-agyria
complex
− − ND − Non-contributory

91. 8 CADASIL
Migraine,
hemisensory
loss
A, M − +
Lacunar infarcts,
subcortical WM,
external capsule and
insula
− − ND −
Non-contributory
9
Frontotemporal
dementia
Dementia A,M − +
Fronto-temporal
atrophy
− − ↓NAA ↑cho −
Non-contributory
10
Limbic
encephalitis
Memory
disturbance
M + −
Cingulate gyrus,
subfrontal cortex and
inferior frontal WM
− − ND −
Pleocytosis,
lymphoma
antibodies in
CSF
11 Hyperammonemia
Confusion,
altered
sensorium
A + −
Posterior cingulate
gyrus
R − ND ND
↑Blood
ammonia
12 Wilson's disease
Weakness,
extrapyrami
dal
symptoms
A, P, L + +
Fronto-parietal lobes,
dorsal midbrain, deep
grey nuclei
R − ND −
↑Serum and
urine copper,
↓ceruloplasmin
13
Myotonic
dystrophy
Developmen
tal delay,
facial and
distal limb
weakness
A − +
Periventricular and
deep WM, prominent
VR spaces
− − ND ND
Myotonic
discharges in
electromyograp
hy

92. A 34-year-old male with herpes encephalitis (a) Coronal T2weighted image
shows bilateral symmetric cortical swelling and hyperintensity involving the
anteromedial temporal lobes including the insular cortex (white arrows) with
characteristic sparing of basal ganglia (open arrows). (b) AxialT2 weighted image
shows additional involvement of orbital gyri (black arrows). (c) Axial diffusion-weighted
image depicts restricted diffusion in the involved areas (white arrows).

93. A 46-year-old male with herpes encephalitis (a) Axial susceptibility-weighted
image demonstrates haemorrhages (black arrows) in both temporal lobes. (b)
Axial T1weighted post-gadolinium image shows gyriform enhancement (white
arrows) in the involved temporal lobes.

94. An 11-year-old female with cytomegalovirus infection(a) Axial fluid-attenuated
inversion-recovery image shows bilateral periventricular cysts
with gliosis of white matter (white arrows) in both temporal lobes. (b)
Axial T2weighted image demonstrates gyral abnormality in the form of
pachygyria–agyria complex (open arrows) bilaterally involving the
temporo-occipital lobes in addition to the periventricular cysts (white
arrows). Combination of these imaging findings along with periventricular
calcifications are in favour of congenital cytomegalovirus infection

95. A 17-year-old male with complex partial seizure(a) Oblique coronal fluid-attenuated
inversion-recovery image reveals bilateral hippocampal atrophy,
hyperintensity indicating gliosis (white arrows) with loss of internal
architecture consistent with a diagnosis of bilateral mesial temporal sclerosis.
(b) Oblique coronalT1 weighted image demonstrates bilateral mamillary body
atrophy (white arrows).

96. A 64-year-old male with memory loss and personality changes (a) Axial fluid-attenuated
inversion-recovery image shows hyperintensity in both anteromedial
temporal lobes (white arrows). (b) Axial T2weighted and (c) coronal T1weighted
images depict marked atrophy of temporal lobes with preferential volume loss of
hippocampi and parahippocampi gyri and corresponding enlargement of
parahippocampal fissures including choroidal (downwards arrows on c) and
hippocampal fissures (black arrows), and temporal horns (white arrow).
Temporal lobe hyperintensity indicates non-specific gliosis because of marked
atrophy; however, the selective mesial temporal atrophy with enlarged
parahippocampal fissures are diagnostic of Alzheimer's disease

97. A 64-year-old female with frontotemporal dementia(a) AxialT2 weighted
image shows hyperintensity with volume loss in bilateral temporal lobes
(black arrows). (b) Axial fluid-attenuated inversion-recovery image
demonstrates predominate volume loss in both frontal and temporal lobes
with associated increased signal in white matter indicating underlying
gliosis (white arrows)

98. A 34-year-old male with myotonic dystrophy Type 1 (a) Axial fluid-attenuated
inversion-recovery image shows bilateral anterior temporal white
matter hyperintensity (black arrows). (b) Coronal T2weighted image shows
hyperintensity in periventricular white matter (white arrow) and prominent
perivascular spaces (open arrows) disproportionate to the age.

99. A 61-year-old male with gliomatosis cerebri (a) Axial T2weighted image
demonstrates cortical expansion and hyperintensity (white arrows) in both
medial temporal lobes. (b) Axial T2 weighted image shows multifocal brain
parenchymal involvement with expansion and relative preservation of
architecture. Involvement of frontotemporal lobes (white arrows), basal
ganglia (open arrows) and thalami (black arrows) are seen. (c) MR
spectroscopy shows markedly elevated myoinositol peak at 3.45 parts per
million.

100. A 17-year-old male with mitochondrial encephalopathy, lactic acidosis and
stroke-like episodes (MELAS)(a) Axial fluid-attenuated inversion-recovery
(FLAIR) image shows bilateral asymmetric cortical and subcortical temporal
lobe hyperintensity (white arrows), right more than the left and (b) axial FLAIR
image 4 months later shows resolution of previous hyperintensity and new area
of involvement on left side (white arrow) indicating the fleeting nature of the
lesions. (c) MR spectroscopy demonstrates elevated lactate peak at 1.3 parts
per million. These findings are consistent with a diagnosis of MELAS

101. A 61-year-old female with hyperammonemic encephalopathy. Axial fluid-attenuated
inversion-recovery images show (a) bilateral peripheral cortical
temporal lobe (white arrows) and (b) right posterior cingulate gyrus (open arrow)
hyperintensity. Diffusion-weighted images show corresponding restricted diffusion
(white arrows) in (c) the bilateral peripheral cortical temporal lobe and (d) the
right posterior cingulate gyrus. The typical distribution of lesions with elevated
blood ammonia level suggests this diagnosis.

102. A 10-year-old male with Wilson's disease. (a) Axial T2weighted and (b) fluid-attenuated
inversion-recovery images demonstrate bilateral extensive cortical
and subcortical temporal lobe hyperintensity (white arrows), dorsal midbrain
involvement (open arrow), bilateral symmetric basal ganglia (yellow arrows)
and anterolateral thalamic (black arrows) hyperintensity. Extensive grey and
white matter lesions are less frequently in Wilson's disease however
concomitant basal ganglia, thalamic and dorsal brainstem abnormalities
point to the diagnosis.

103. A 22-year-old male with megalencephalic leukoencephalopathy with
subcortical cysts. (a) Axial fluid-attenuated inversion-recovery and (b)
axial T2weighted images reveal bilateral anterior temporal lobe cysts (white
arrows), deep (black arrow) and subcortical (open arrow) white matter
hyperintensity. Temporal lobe cysts with extensive white matter lesions
involving the deep and subcortical white matter, and external capsule with
sparing of basal ganglia, thalami and internal capsules are typical for this
subtype of van der Knaap leukoencephalopathy.

104. A 35-year-old female with cerebral autosomal dominant arteriopathy with
subcortical infarcts and leukoencephalopathy. (a) Axial T2weighted image shows
confluent hyperintense lesions in both anterior temporal lobes (open arrows). (b)
Axial fluid-attenuated inversion-recovery image shows patchy subcortical
hyperintense areas (white arrows) and multiple lacunar infarcts (thin white
arrow). (c) AxialT2 weighted image shows multiple patchy hyperintense areas
involving the external capsule (open arrow), insular cortex (thin arrow) and
basal ganglia (asterisk).

105. A 26-year-old male with paraneoplastic limbic encephalitis presenting
with progressive memory disturbance. (a) Initial coronal T2weighted
image demonstrates swelling and increase signal in both mesial temporal
lobes (white arrows). (b) Follow-up coronal T2weighted image after 1
year shows significant decrease in the swelling and abnormal signal
intensity (white arrows). (c) Axial contrast-enhanced CT section through
the mid-abdomen shows ileocolic intussusception (black arrow) with
marked concentric wall thickening of ascending colon (white arrows).
Biopsy proven Burkitt's lymphoma of ascending colon is also shown.

106. Temporal and frontal lobe seizures differential semiological features.
Features Temporal Frontal
Sz frequancy Less frequent Often daily
Sz onset Slower Abrupt, explosive
Sleep activation Less common Characteristic
Progression Slower Rapid
Automatisms Common-longer Less common
Initial motionless stare Common Less common
Complex postures Late, less frequent, less prominent Frequent, prominent, and early
Hypermotor Rare Common
Bipedal automatisms Rare Characteristic
Somatosensory Sx Rare Common
Vocalization Speech (nondominant)
Loud, nonspeech (grunt, scream,
moan)
Seizure duration Longer Brief
Secondary generalization Less common Common
Postictal confusion More prominent-longer Less prominent, Short
Postictal aphasia Common in dominant hemisphere Rare unless spreads to temporal lobe

107. Semiological Features (TLE) - Lateralizing or Localizing Value.
Feature Location
Automatism
Unilateral limb automatism Ipsilateral focus
Oral automatism (m)Temporal lobe
Unilateral eye blinks Ipsilateral to focus
Postictal cough Temporal lobe
Postictal nose wiping Ipsilateral temporal lobe
Ictal spitting or drinking Temporal lobe focus (R)
Gelastic seizures
(m)Temporal, hypothalamic, frontal
(cingulate)
Dacrystic seizures (m)Temporal, hypothalamic
Unilateral limb automatisms Ipsilateral focus
Whistling Temporal lobe

108. Autonomic
Ictal emeticus Temporal lobe focus (R)
Ictal urinary urge Temporal lobe focus (R)
Piloerection Temporal lobe focus (L)
Speech
Ictal speech arrest
Temporal lobe (usually
dominant hemisphere)
Ictal speech preservation Temporal lobe (usually
nondominant)
Postictal aphasia
Temporal lobe (dominant
hemisphere)

109. Motor
Early nonforced head turn Ipsilateral focus
Late version Contralateral focus
Eye deviation Contralateral focus
Focal clonic jerking Contralateral perirolandic focus
Asymmetrical clonic ending Ipsilateral focus
Fencing (M2E)
Contralateral (supplementary
motor)
Figure 4
Contralateral to the extended limb
(temporal)
Tonic limb posturing Contralateral focus
Dystonic limb posturing Contralateral focus
Unilateral ictal paresis Contralateral focus
Postictal Todd’s paresis Contralateral focus

110. CORRESPONDENCE OF COGNITIVE FUNCTIONS
EVALUATED BY MMSE TO SPECIFIC BRAIN AREAS