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Temporal lobe and its role in psychiatry
The temporal lobe is involved in processing sensory input, memory formation, language comprehension, and emotional processing. It contains structures like the hippocampus and amygdala that are important for memory and emotional associations. Disorders of the temporal lobe can cause problems like epilepsy, memory deficits, language issues like aphasia, and behavioral changes. Temporal lobe epilepsy is a common type of seizure originating in structures of the anteromedial temporal lobe. Bilateral damage to the amygdala and inferior temporal cortex can cause Klüver-Bucy syndrome characterized by changes in behavior and cognition. The temporal lobe also plays a key role in conditions like Alzheimer's disease, frontotemporal dementia, and traumatic brain injury.
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Temporal lobe and its role in psychiatry
- 1. TEMPORAL LOBE AND ITSROLE 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 ofthe 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 belowthe Sylvain Fissure and anterior to the occipital cortex • Subcortical Temporal Lobe Structures – Limbic cortex – Amygdala – Hippocampal Formation
- 5. • Brodmann areason 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 • TwoSulci – Superior temporal sulcus – Inferior temporal sulcus • Three Gyri – Superior temporal gyrus – Middle temporal gyrus – Inferior temporal gyrus
- 7. • The lateraltemporal 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 onLateral Aspect
- 12. Medial Aspect • Fusiformgyrus • Hippocampal gyrus • Amygdala • Dentate Gyrus • Inferior Temporal Gyrus
- 13. Medial Surface ofTemporal Lobe
- 14. Functional Areas onMedial 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: Theassociation 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 isa 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 • Partof 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 • Thelateral 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 • TheSuperficial 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.
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- 28. Connections of TemporalLobe 1. Hierarchical sensory pathway 2. Dorsal auditory pathway 3. Polymodal pathway 4. Medial temporal pathway 5. Frontal lobe projection
- 29. • Hierarchical SensoryPathway – 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 LobeProjection – Auditory and Visual Cortex to the Frontal Lobe – Movement Control – Short-term Memory – Affect
- 32. Papez Circuit Cingulate gyrus Parahippocampalgyrus and Amygdala Hippocampus Fornix Mamillary body Anterior nucleus of Thalamus Cingulate gyrus.
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- 34. • Functions ofPapez circuit : – Controls emotion, behaviour and drive. – Also takes part in memory.
- 35. Functions of TemporalLobe • 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
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- 38. Tests for VisualProcessing Meier & French test Gottschaldt Hidden figure test Rey Complex figure test Mooney Closure test
- 39. Verbal Memory • RevisedWechsler 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 ReyComplex Figure
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- 42. DISORDERS OF TEMPORALLOBE 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 symptomsof 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 auditoryperception • 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 ofanterior 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 ofTLE • 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 psychiatricillness :- • 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 Resultsdue 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 Memorydisturbances 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 disturbancein 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 • Alsoknown 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 isimpaired, 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 medialand 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 leftside 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 andasponteinity 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 • Mostcommon 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 andBehavioural 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 Injuryof 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 lobeis 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 andSadock’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.
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