Temporal lobe and its role in psychiatry and related disorders

1. TEMPORAL LOBE AND
ITS ROLE IN PSYCHIATRY
Chairperson: Dr. N. Heramani Singh
Professor & HOD
Dept. of Psychiatry, RIMS
Presenter: Dr. Kaushik Nandi

2. Contents
• Introduction
• Anatomy
• Connections of Temporal Lobe
• Temporal Lobe testing
• Temporal Lobe Epilepsy
• Klüver–Bucy syndrome
• Wernicke’s Aphasia
• Dysfunction of Memory
• Alzheimer’s disease
• FrontoTemporal Dememtia
• Traumatic Brain injury and ADHD

3. Introduction
• One of the four major lobes of cerebral cortex
• 22% of whole cerebral cortex volume
• Processing sensory input into derived meaning
• Appropriate retention of visual memory
• Language comprehension
• Emotional association
• Seat of human para-psychological and psychic
abilities

4. Anatomy
• Located below the Sylvain Fissure and anterior to the
occipital cortex
• Subcortical Temporal Lobe Structures
– Limbic cortex
– Amygdala
– Hippocampal Formation

5. • Brodmann areas on lateral surface
of Temporal lobe –
- Auditory areas
( area 41, 42)
- Auditory association cortex
( area 22)
- Ventral visual stream areas
( area 20, 21, 37 & 38 )

6. Lateral Aspect
• Two Sulci
– Superior temporal sulcus
– Inferior temporal sulcus
• Three Gyri
– Superior temporal gyrus
– Middle temporal gyrus
– Inferior temporal gyrus

7. • The lateral temporal surface has three gyri:-
– Superior temporal gyrus - Area 22.
– Middle temporal gyrus - Area 21.
– Inferior temporal gyrus - Area 20.
• These gyri terminate anteriorly at the temporal pole -
Area 38.
• The superior temporal gyrus lies between the Sylvian
Fissure and the Superior temporal sulcus.
• The angular gyrus, a parietal lobe structure, caps the
upturned posterior end of the superior temporal sulcus.

8. Superior Temporal Gyrus
• 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. Middle Temporal Gyrus
• The region encompasses most of the lateral
temporal cortex.
• Believed to play a part in auditory processing
and language.
• Language function is left lateralized in most
individuals.
• Brodmann area 21.

10. 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. Functional Areas on Lateral Aspect

12. Medial Aspect
• Fusiform gyrus
• Hippocampal gyrus
• Amygdala
• Dentate Gyrus
• Inferior Temporal Gyrus

13. Medial Surface of Temporal Lobe

14. Functional Areas on Medial Aspect

15. Amygdala
• Amygdala = Greek for
almond
• Medial aspect of the
temporal lobe
• Located at anterior end of
hippocampal formation
• Consists of a cortical part
(cortical nucleus) and
a nuclear part

16. Contd…
• Inputs: The association areas of visual,
auditory, and somatosensory cortices are main
inputs to amygdala
• Outputs: The hypothalamus and brainstem
autonomic centers including the vagal nuclei
and the sympathetic neurons are main output

17. Functions of Amygdala
• Emotional learning
• Memory modulations
Neuropsychological correlates of Amygdala
activity
• Sexual orientation
• Aggression
• Fear
• Alcoholism and binge drinking
• Anxiety
• Post-traumatic stress disorder

18. Hippocampus
• Hippocampus is a scrolled structure located in the medial
temporal lobe
• In cross section resembles a ‘sea horse’ (for which it is
named)
• Can be divided into six different areas
1. Dentate gyrus :- Dense dark layer of cells at tip of
hippocampus
2. Cornu ammonis (ram's horn shape) Area1 (CA1)
3. CA 2
4. CA 3
5. CA 4
6. Subiculum - at base of hippocampus and continuous
with entorhinal cortex, which is part of para-
hippocampal gyrus

20. Functions of Hippocampus
• Medial temporal lobe memory system – includes
hippocampus and adjacent cortex, Parahippocampal gyrus
and perirhinal regions.
• This memory system is involved in the storage of new
memories.
• Hippocampus is critical for long-term memory storage.
• Declarative(Explicit)memory - hippocampus, fornix,
corpus mammilare
• Non-declarative (Implicit) memory - basal ganglia ,
limbic system, cerebellum, cerebral cortex and also in
hippocampus

21. • Mechanism – Long term potentiation (LTP )
– persistent strengthening of synapses based on
recent patterns of activity
• Hippocampal Damage – Affects nearly both,
but procedural (Implicit) memory formations
are more affected.

22. DENTATE GYRUS
• Part of Hippocampal formation
• Contains granule cells, which project to the pyramidal
cells and interneurons of the CA3
• Granule cells are the principal excitatory neurons of the
dentate gyrus
• Major input to the dentate gyrus (Perforant pathway)
is from the entorhinal cortex (receives no direct inputs
from other cortical structures)
• Dentate gyrus is one of the few regions of the brain
where neurogenesis takes place. Neurogenesis is
thought to play a role in the formation of new memories

23. Arterial Supply
• The lateral aspect is perfused mainly by the
branches of the MCA –
• Anterior temporal A.
• Middle temporal A.
• Temporo-occipital A.
• The inferior temporal gyrus is supplied by
branches of the PCA.
• The choroid plexus of the temporal horn is
supplied by the branches of the anterior choroidal
A.

24. Blood Supply
Lateral Surface – Inferior branch of MCA

25. Blood Supply
Medial & Inferior Surface – Temporal branch of PCA

26. Venous Drainage
• The Superficial middle cerebral V. 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
sup middle cereb V. to the superior sagittal sinus.
• An Inferior anastomotic vein of Labbe runs over the
temporal lobe and connects the sup middle cereb V. to
the transverse sinus.
• A few Inferior cerebral veins drain the inferior aspect.
They anastomose with basal veins and middle cerebral
veins and drain into cavernous, transverse and superior
petrosal sinuses.

27. Venous Drainage

28. Connections of Temporal Lobe
1. Hierarchical sensory pathway
2. Dorsal auditory pathway
3. Polymodal pathway
4. Medial temporal pathway
5. Frontal lobe projection

29. • Hierarchical Sensory Pathway
– Incoming Auditory and Visual
Information
– Stimulus Recognition
• Dorsal Auditory Pathway
– From Auditory cortex to Posterior
Parietal lobe
– Detection of spatial
location/movement

30. • Polymodal Pathway
– From Auditory and Visual
Areas to the Polymodal
regions of Superior temporal
sulcus
– Stimulus Categorization
• Medial Temporal Projection
– From Auditory and Visual
Areas to the medial temporal
lobe, limbic cortex,
hippocampal formation, and
amygdala
– Hippocampal projections
forms the Perforant Pathway
– Long-term Memory

31. • Frontal Lobe Projection
– Auditory and Visual Cortex
to the Frontal Lobe
– Movement Control
– Short-term Memory
– Affect

32. Papez Circuit
Cingulate gyrus
Parahippocampal gyrus and Amygdala
Hippocampus
Fornix
Mamillary body
Anterior nucleus of Thalamus
Cingulate gyrus.

33. Papez Circuit

34. • Functions of Papez circuit :
– Controls emotion, behaviour and drive.
– Also takes part in memory.

35. Functions of Temporal Lobe
• SPECIAL SENSES
– Hearing
• FUNCTIONS OF HIPPOCAMPUS
– Memory storage, long term potentiation of memory
• FUNCTIONS OF LIMBIC SYSTEM
– Emotions & Mood
– Memory
– Attitudes & Social Behavior
• LANGUAGE FUNCTIONS
– Semantics
– Naming
• VISUAL & OTHER SENSORY INTEGRATION

36. Temporal Lobe Testing

37. Dichotic listening task

38. Tests for Visual Processing
Meier & French test
Gottschaldt Hidden figure test
Rey Complex figure test
Mooney Closure test

39. Verbal Memory
• Revised Wechsler Memory Scale-
A person's performance is reported as five Index
Scores:
1. Auditory Memory
2. Visual Memory
3. Visual Working Memory
4. Immediate Memory
5. Delayed Memory

40. Non verbal memory
Rey Complex Figure

41. Non-verbal Memory (example)

42. DISORDERS OF TEMPORAL LOBE
 Disorders of Auditory Perception
 Temporal lobe Personality and Visual field defects
 Temporal lobe epilepsy (TLE)
 Kluver-Bucy syndrome
 Dementia:- Alzheimer’s disease
Frontotemporal dementia (FTD)
 Amnestic disorder
 Damage from traumatic brain injury (TBI)
 Temporal lobe tumour
 Affective disorders
 ADHD

43. 8 principle symptoms of Temporal
lobe damage
1. Disturbance of auditory sensation and perception
2. Disturbance of selective attention of auditory and
visual input
3. Disorders of visual perception
4. Impaired organization and categorization of verbal
material
5. Disturbance of language comprehension
6. Impaired long-term memory
7. Altered personality and affective behaviour
8. Altered sexual behaviour

44. 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
• There may be disturbance of visual and auditory input
selection. This presents as impairment of short term memory,
also called working memory and judgment about the recency
of events.

45. Affect
• Stimulation of anterior and medial temporal cortex produces
feelings of fear
Temporal Lobe Personality
(Gastaut-Geschwind syndrome)
– Hypergraphia- personality that overemphasizes in writing
their trivial and petty details of life.
– Hyper-religiosity
– Pedantic speech (an overly formal speaking style
inappropriate to the conversational setting)
– Egocentricity (preoccupation with one’s own internal world)
– Perseveration, circumstantiality
– Altered sexuality (mainly hypo, though hypersexuality also
reported)
– Paranoia
– Proneness to aggression

46. Temporal Lobe Epilepsy
Definition: a condition characterized by recurrent
unprovoked seizures originating from the antero-
medial aspect of temporal lobe(Hippocampus, Para-
hippocampal gyrus, Amygdala)
• Commonest type of seizure - > Approx. 25% of all
epilepsies
• Begins in late childhood or early adulthood
• Complex partial / psychomotor seizure
• Often resistant to pharmacotherapy.
• Described by Hughlings-Jackson

47. Causes of TLE
1. Hippocampal sclerosis (mesial temporal sclerosis or
Ammon’s horn sclerosis) most frequent , accounting
for 50–70% , has strongly associated with a history of
childhood febrile convulsions
2. Dysembryoplastic neuro-epithelial tumours,
3. Cavernous angiomas,
4. Gliomas,
5. Cortical dysplasia and gliosis secondary to
encephalitis or meningitis
6. Alcohol withdrawal
7. Head injury

48. Clinical features of TLE
• Produce the most varied and complex auras of all and
many are highly characteristic.
• Often contain elements that echo symptoms seen in
psychiatric disorder.
• Simple and complex partial seizures, with both occurring
in some 70% of patients.
• Characteristically have a gradual onset, usually feature a
conspicuous motionless stare and are relatively
prolonged, with automatisms often continuing for 2
minutes, occasionally even longer.

49. SEQUELE OF TLE
1. Post-ictal psychosis:- Brief self-limiting
episodes of psychosis that are of abrupt onset and
follow seizure.
• Mixed psychotic and affective features, most
notably agitation, following a brief lucid interval
after seizures.
• Most common form of psychosis in patients with
epilepsy
• Tend to recur and a significant minority of
patients will eventually develop chronic interictal
psychosis

50. 2. Inter-ictal psychiatric illness :-
• Depression : Common in people with epilepsy,
especially those with poorly controlled seizures
particularly with TLE
• Anxiety
• Suicide
• Schizophrenia like psychosis
• Personality syndrome: (Gastaut-Geschwind’s
syndrome)
 Treatment of TLE :-
• 1.Antiepileptics
• 2.Surgery: Temporal lobectomy

51. Klüver–Bucy syndrome
 Results due to a bilateral destruction of the amygdaloid
body and inferior temporal cortex. In humans, it was first
documented in patients with temporal lobectomy.
 It is characterized by :-
• Visual agnosia
• Placidity
• Hypermetamorphosis
• Hyperorality
• Hypersexuality
• Amnesia ( both anterograde and retrograde )
 Causes:- Cerebral trauma, Infections including herpes and
other encephalities, Alzheimer's disease and other
dementias, Niemann-Pick disease and Cerebrovascular
disease.

52. Speech and Memory disturbances
inTemporal lobe disease
• Dominant temporal lobe lesion:-
– Wernicke’s aphasia.
– Dysfunctions of memory.
• Non-dominant temporal lobe lesion:-
– Agnosia for sounds.
– Dysprosody- Disturbed emotional and
affective components of language or ‘body
language’.

53. Aphasia
Defination: Any disturbance in the comprehension or
expression of language caused by a brain lesion.
• NON-FLUENT 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. Comprehension is intact.
• FLUENT APHASIA i.e. in lesion to Wernicke's area
may result in, in which a person speaks normally, and
sometimes excessively, but uses jargon and invented
words, that make little sense. The person also fails to
comprehend written and spoken words.

54. Wernicke’s Aphsia
• Also known as Fluent / Receptive / Sensory / Post-
rolandic Aphasia
• Due to destruction of postero-superior temporal area (
Broadmann area 22) of the dominant hemisphere
supplied by inferior division of MCA.
–Fluency is preserved with a normal or even
increased word output (Logorrhea)
–Speech although effortless is devoid of
meaningful content
–Paraphasias, Neologisms and defective
sentence structure (Paragrammatism)
(Jargon aphasia)

55. Contd…
–Auditory comprehension is impaired, even
unaware of his own speech, and does not
correct himself.
–Repetition impaired
–Reading impaired
–Naming impaired
–Writing impaired
–Patient often is unaware of the defect

56. Dysfunction of memory
• Hippocampus is related to converting recent memory
to long-term memory.
• Lesion in hippocampus causes affected person unable
to store newly acquired long-term memory –>
Anterograde amnesia.
• Memory of remote past events before the lesion
developed is unaffected.
• Visual memory (Picture/scene recall)–Right
Parahippocampal cortex.
• Verbal memory (Word recall)– Left Parahippocampal
cortex.

57. Contd…
• 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.
• There is difficulty recalling information.

58. Contd…
• The left side is responsible for verbal material and
the right for non-verbal memory such as faces,
tunes and drawings.
• Injury to auditory cortex produces cortical
deafness - auditory agnosia and difficulty in
localizing source of sound.
• Noticeable deficit occurs only when there is b/l
damage.
• Damage to temporo-parietal junction causes
auditory inattention.

59. Temporal Lobe Tumors
• Perhaps produce the highest frequency of mental
disturbances including behavioral and personality
changes.
• Associated with Seizure or may be completely
unrelated to seizure activity.
• Dominant temporal lobe tumors tend to produce the
greater cognitive disturbances both verbal and non-
verbal functions than non-dominant.

60. Symptoms:-
• Slowing and asponteinity of speech and movement
• Pure amnesia, florid Korsakoff syndrome
• Affective disturbances are common
• Psychotic illness resembling schizophrenia
• Auditory hallucinations and atypical dream-like
episodes, depersonalization, blanking-out spells, and
dazed feelings
• Visual hallucinations occurring within a hemianopic
field of vision
• May present with depression
• Personality changes may occur

61. Alzheimer’s Disease
• Most common form of dementia (cortical
dementia)
• Multifactorial causes :-
1. Genetic:- Chromosome 21 mutation
2. Amyloid beta protein and synapse loss
3. Other possible factors: Old age, head trauma,
inflammation, oxidative stress, etc.
• Atrophy in the posterior temporal cortex, parietal
lobe and frontal lobe is often most prominent

62. Clinical Features
• Cognitive: mental decline, difficulty thinking and
understanding, confusion, delusion, disorientation,
forgetfulness, making things up, difficulty
concentrating, inability to create new memories, or
inability to recognise common things
• Behavioural: aggression, agitation, difficulty with
self care, irritability, personality changes, lack of
restraint or wandering and getting lost
• Mood: anger, apathy, general discontent, loneliness
or mood swings

63. Contd…
• Psychological: depression, hallucination or paranoia
• Whole body: loss of appetite or restlessness
• Also common: behavioral symptoms, inability to
combine muscle movements, or jumbled speech
Treatment :-
1. Cholinesterase inhibitors: Donepezil, Rivastigmine
2. Non-competitive NMDA receptor antagonist:
Memantine
3. Vitamin E

64. FrontoTemporal Dementia (FTD)
• First described by Arnold Pick.
• Pick’s Disease
• Characterised by progressive circumscribed
atrophy of frontal and temporal lobe cortices
• Sporadic and familial
• Familial: Autosomal dominant (50%)
• Related to Chromosome 17.

65. • Personality and Behavioural changes
• Relative preservation of other cognitive
functions
• Onset : before 75 years, familial cases have an
earlier onset
• Features of Kluver-Bucy syndrome are more
common in FTD than Alzheimer’s disease

66. Course and Treatment
• Progressive deterioration.
• No promising treatments for the cognitive deficits
• Target can be to prevent progression of the underlying
etiology, if detected.
• Recommend cholinesterase inhibitors or Memantine.
• Symptomatic use of Trazodone, atypical antipsychotics,
SSRIs, and anticonvulsants may help agitation,
disinhibition, and aggressive behaviour.
• Family support

67. Traumatic Blunt Injury of
Temporal Lobe
• Caused by a blunt force, a fall, concussive waves
through the air (usually an explosion) severe whiplash,
toxins or infections.
• Symptoms :- Include all of the above temporal lobe
disorder symptoms, plus difficulty recognizing faces
(prosopagnosia) short-term memory loss and aggressive
behaviour.
• Also can cause epilepsy and progressive disorders such
as pugilistic Parkinson's disease in the long term.

68. Attention Deficit Hyperactivity
Disorder
• Enlarged hippocampus represent a compensatory
response to the presence of disturbances in
perception of time, temporal processing and
stimulus seeking symptoms.
• Disrupted connections between Amygdala and
Orbitofrontal cortex may contribute to
behavioural disinhibition
• Still debated role in ADHD, topic of research
interest present days.

69. Summary
• Temporal lobe is associated with the function of
Hearing, Memory, Emotions, Mood, Behavior,
Language function, Visual and other sensory
integration
• Disorder of Personality: Gastaut-Geschwind
syndrome
• Temporal Lobe epilepsy & Kluver-Bucy syndrome
• Disorder of Speech: Wernicke’s aphasia
• Dementia: Alzheimer’s dementia & Frontotemporal
dementia

70. References
1. Kaplan and Sadock’s Comprehensive Textbook of
Psychiatry, 9th edition.
2. Kaplan and Sadock’s Synopsis of Psychiatry,10th
edition.
3. Snell’s Clinical Neuroanatomy,7th edition.
4. Grays Anatomy, 40th edition.
5. Fundamentals of Human Neuropsychology - Bryan Kolb
& Ian Q. Whishaw
6. Various internet sites.

71. THANK YOU