Transcript Blumenfeld – Chapter 18 Limbic System: Homeostasis

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-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
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  reversallearning / task switching
Clinical Anatomy 500
•
Which pattern of olfactory loss (left, right,
bilateral) would be caused by lesions at
the following sites?
1)
2)
3)
4)
5)
Left olfactory mucosa
Left olfactory bulb
Left olfactory tract
Left primary olfactory cortex
Left thalamus
Clinical Anatomy 500
Clinical Anatomy 500
1)
2)
3)
4)
5)
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
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
2) Alvear pathway
Entorhinal cortex

Dentate gyrus

Hippocampus (CA1&3)

Subiculum

Entorhinal cortex
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
Which pathway connects the following
structure to the amygdala?
Structure
1. Orbital frontal cortex
2. Hypothalamus and
the septal region
3. Brainstem
Pathway
A. Uncinate fasciculus
B. Stria terminalis and
amygdalofugal
pathway
C. 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
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