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– Corticomedial, basolateral, central, bed nucleus of the

stria terminalis

• Diencephalon– Hypothalamus, thalamus (anterior and mediodorsal

nuclei), habenula

• Basal ganglia – Ventral striatum, ventral pallidum

Limbic structures

• Basal forebrain– 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-JeopardyClinical 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

Clinical Anatomy 300

• Name 2 intracerebral vascular lesions which could lead to memory deficits

Clinical Anatomy 300

1) Rupture of A-com aneurysm (disrupt basal forebrain, medial diencephalon, and frontal lobes)

2) Top of the basilar artery lesions (b/l medial temporal or medial diencephalic supplied by PCA)

3) 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?

1) Left olfactory mucosa

2) Left olfactory bulb

3) Left olfactory tract

4) Left primary olfactory cortex

5) Left thalamus

Clinical Anatomy 500

Clinical Anatomy 500

1) Left olfactory mucosa left sided loss

2) Left olfactory bulb left sided loss

3) Left olfactory tract left sided loss

4) Left primary olfactory cortex no loss

5) Left thalamus no loss

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

1) Perforant pathway

Entorhinal cortex

Dentate gyrus

Hippocampus (CA1&3)

Subiculum

Entorhinal cortex

2) Alvear pathway

Entorhinal cortex

Hippocampus (CA1&3)

Subiculum

Entorhinal cortex

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

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

Pathway

A. Uncinate fasciculus

B. Stria terminalis and amygdalofugal pathway

C. Medial forebrain bundle

Structure

1. Orbital frontal cortex

2. Hypothalamus and the septal region

3. Brainstem

Which pathway connects the following structure to the amygdala?

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

1) Thiamine

2) Alcoholics and patients with malnutrition

3) 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