Chenjie Xia (R2) Academic ½ Day Wednesday, April 7th, 2010 Blumenfeld – Chapter 18 Limbic System: Homeostasis, Olfaction, Memory, and Emotion Chenjie Xia (R2) Academic ½ Day Wednesday, April 7th, 2010

Review of key structures

Overview of limbic structures

Overview of limbic structures

Overview of limbic structures

Limbic structures Amygdala nuclei Diencephalon Basal ganglia Corticomedial, basolateral, central, bed nucleus of the stria terminalis Diencephalon Hypothalamus, thalamus (anterior and mediodorsal nuclei), habenula Basal ganglia Ventral striatum, ventral pallidum Habenula: small epithalamic structure located just lateral to the pineal gland.

Limbic structures Basal forebrain Septal Region Brainstem nuclei Nucleus basalis of Meynert, olfactory tubercle, nucleus of diagonal band of Broca, preoptic area, portions of amygdala Septal Region Medial septal nucleus, lateral septal nucleus, nucleus accumbens Brainstem nuclei Interpeduncular, superior central, dorsal and ventral tegmental, parabrachial, periaqueductal gray, reticular formation, nucleus solitarius, dorsal motor nucleus of vagus

Overview of limbic circuitry

The Return of Neuro-Jeopardy! (No more Meryl Streep questions…)

Neuro-Jeopardy Clinical anatomy Book anatomy Syndromes Miscellaneous 100 100 100 100 200 200 200 200 300 300 300 300 400 400 400 400 500 500 500 500

Clinical Anatomy

Clinical Anatomy 100 Where did Dr. Brenda Milner obtain her undergraduate degree and what did she major in? A) Oxford, philosophy B) Cambridge, psychology C) McGill, physiology D) University of Montreal, biology

Clinical Anatomy 100 Where did Dr. Brenda Milner obtain her undergraduate degree and what did she major in? A) Oxford, philosophy B) Cambridge, psychology C) McGill, physiology D) University of Montreal, biology

Clinical Anatomy 200 Bilateral lesions of medial temporal and diencephalic structures would impair which of the following? A) Mediate working memory B) Consolidate long-term explicit memory C) Consolidate long-term implicit memory D) Retrieve long-term explicit memory E) Retrieve long-term implicit memory

Clinical Anatomy 200 Bilateral lesions of medial temporal and diencephalic structures would impair which of the following? A) Mediate working memory B) Consolidate long-term explicit memory C) Consolidate long-term implicit memory D) Retrieve long-term explicit memory E) Retrieve long-term implicit memory Think of what HM can and cannot do

Clinical Anatomy 300 Name 2 intracerebral vascular lesions which could lead to memory deficits

Clinical Anatomy 300 Rupture of A-com aneurysm (disrupt basal forebrain, medial diencephalon, and frontal lobes) Top of the basilar artery lesions (b/l medial temporal or medial diencephalic supplied by PCA) Artery of Percheron lesion / single paramedian thalamoperforator artery (b/l medial thalami)

Clinical Anatomy 300 http://www.ajnr.org/cgi/content-nw/full/24/10/2005/F4

Clinical Anatomy 400 Which function has Dr. Brenda Milner has discovered for each of the following structures? 1) Medial temporal lobes 2) Right temporal lobe 3) Left frontal lobe 4) Dorsolateral frontal lobes

Clinical Anatomy 400 Which function has Dr. Brenda Milner discovered for each of the following structures? 1) Medial temporal lobes  explicit memory 2) Right temporal lobe  visuospatial memory 3) Left frontal lobe  verbal fluency 4) Dorsolateral frontal lobes  reversal-learning / task switching

Clinical Anatomy 500 Which pattern of olfactory loss (left, right, bilateral) would be caused by lesions at the following sites? Left olfactory mucosa Left olfactory bulb Left olfactory tract Left primary olfactory cortex Left thalamus Primary olfactory cortex (piriform and periamygdaloid cortex)

Clinical Anatomy 500 Olfactory mucosa  cribriform plate  glomeruli of olfactory bulb  olfactory tract (anterior olfactory nucleus)  to ipsilateral olfactory areas and contralateral olfactory bulb (via medial olfactory stria and anterior commissure) Primary olfactory cortex: piriform and periamygdaloid cortex

Clinical Anatomy 500 Left olfactory mucosa  left sided loss Left olfactory bulb  left sided loss Left olfactory tract  left sided loss Left primary olfactory cortex  no loss Left thalamus  no loss Olfaction: only sensory modality which bypasses thalamus

Book Anatomy

Book Anatomy 100 What are the two main pathways connecting the hippocampal formation and the entorhinal cortex?

Book Anatomy 100

Book Anatomy 100 Perforant pathway Entorhinal cortex  Dentate gyrus Hippocampus (CA1&3) Subiculum 2) Alvear pathway Entorhinal cortex  Hippocampus (CA1&3) Subiculum

Book Anatomy 200 What are the 3 main targets of axons travelling forward in the fornix? Where do axons travelling backward in the fornix originate from?

Book Anatomy 200

Book Anatomy 200 Axons travelling forward in the fornix: 1) subiculum  postcommissural fornix  mammillary nuclei 2) subiculum & hippocampus  precommissural fornix  lateral septal nucleus 3) Fornix  anterior thalamic nucleus Axons travelling backward in the fornix: Medial septal nucleus  hippocampal formation Lateral septal nucleus project richly to medial septal nucleus. Thus, the loop completes itself!

Book Anatomy 300 True or False: HM’s bilateral medial temporal lobectomy was performed by Dr. Wilder Penfield at the Montreal Neurological Institute.

Book Anatomy 300 False. It was done by Dr. William Scoville in Hartford, Connecticut

Book Anatomy 400 Which pathway connects the following structure to the amygdala? Structure Orbital frontal cortex Hypothalamus and the septal region Brainstem Pathway Uncinate fasciculus Stria terminalis and amygdalofugal pathway Medial forebrain bundle

Book Anatomy 400

Book Anatomy 500 Name all the structures involved in the Papez circuit BONUS: Describe the connections between these structures in the Papez circuit…

Book Anatomy 500 http://upload.wikimedia.org/wikipedia/commons/thumb/9/95/Papez_Circuit.jpg/400px-Papez_Circuit.jpg

Syndromes

Syndromes 100 Which syndrome is caused by bilateral lesions of the amygdala and adjacent temporal structures? What are its main characteristics?

Syndromes 100 Kluver-Bucy syndrome: Placid, tame, non-aggressive behaviour Hyperorality Hypersexuality Visual agnosia

Syndromes 200 Who was Dr. Milner’s PhD thesis supervisor? A) Dr. Donald Hebb B) Dr. Wilder Penfield C) Dr. Herbert Jasper D) Dr. Henry Gustave Molaison E) Dr. William Osler

Syndromes 200 Who was Dr. Milner’s PhD thesis supervisor? A) Dr. Donald Hebb B) Dr. Wilder Penfield C) Dr. Herbert Jasper D) Dr. Henry Gustave Molaison E) Dr. William Osler

Syndromes 300 Regarding the Wernicke Korsakoff syndrome: 1) Which substance is deficient? 2) Who are at risk for developing it? 3) What is the typical clinical triad?

Syndromes 300 Thiamine Alcoholics and patients with malnutrition Confusion, opthalmoplegia, ataxia

Syndromes 400 A previously healthy 64 yo man presents with an episode of 4 hours during which the wife witnessed him as repeatedly asking the same questions. He then returned to normal, but with complete amnesia of the episode. What is the most likely diagnosis? What are the main DDx?

Syndromes 400 TGA DDx: TIA Seizure Migraine

Syndromes 500 Which of the following tasks completed by HM provided Dr. Milner the insight for the theory of multi-system memory? A) Learning a maze path through trial and error B) Learning to trace a star shape through a mirror reflection C) Successfully completing the Wisconsin Card Sorting Test

Syndromes 500 Which of the following tasks completed by HM provided Dr. Milner the insight for the theory of multi-system memory? A) Learning a maze path through trial and error B) Learning to trace a star shape through a mirror reflection C) Successfully completing the Wisconsin Card Sorting Test

Miscellaneous

Miscellaneous 100 What are the 4 main functions of limbic system and their corresponding key structure?

Miscellaneous 100 Mnemonic: HOME

Miscellaneous 200 Which type of memory is invoked in the following situations (explicit vs implicit)? 1) A medical student impressing the attending by listing a full list of DDx for HA at neurology rounds 2) A neurology resident successfully retrieving CSF on first attempt in a agitated encephalopathic patient with a BMI of 35 3) An IM resident breaking into cold sweats every time a Code Blue is called

Miscellaneous 200 1) A medical student impressing the attending by listing a full list of DDx for HA at neurology rounds  Explicit 2) A neurology resident successfully retrieving CSF on first attempt in a agitated encephalopathic patient with a BMI of 35  Implicit (skills) 3) An IM resident breaking into cold sweats every time a Code Blue is called  Implicit memory (classical conditioning)

Miscellaneous 200

Miscellaneous 300 Which region of the parahippocampal gyrus serves as the most important relay between the hippocampal formation and association cortices? A) Piriform and periamygdaloid cortex B) Entorhinal cortex C) Parahippocampal cortex D) Perirhinal cortex E) Orbital frontal cortex

Miscellaneous 300

Miscellaneous 400 Name the 3 components of the hippocampal formation?

Miscellaneous 400 3 components of the hippocampal formation: 1) Subiculum 2) Hippocampus (proper) 3) Dentate gyrus

Miscellaneous 400

Miscellaneous 400

Miscellaneous 500 Who were PB and FC?

Miscellaneous 500 Who were PB and FC? PB: civil engineer; FC: glove-cutter Patients with anterograde amnesia following left medial temporal lobectomy (1941) performed by Dr. Penfield for refractory epilepsy Hypothesized to have baseline right medial temporal atrophy, thus functional bilateral medial temporal lesions following Sx