Download Limbic System

Hypothalamus
And
Limbic System
ANHB 2217 – 2006
Avinash Bharadwaj
Hypothalamus
 A small area with great
activity
 Crossroads :
 Somatic and visceral activity
 Emotion and responses
 Olfaction, memory and
responses
 Short- and long control loops
 “Preservation”
 Feeding
 Hunger and satiety
 Defence
 Somatic and visceral
activity
 Reproduction
 Sex drive and autonomic
responses
 Homoeostasis
 Temperature and osmolar
regulation
Hypothalamus :
Topography
A
Medial Zone
Posterior
Dorsomedial
Ventromedial
Mamillary body
Column of fornix
Paraventricular
Anterior
Supraoptic
Pituitary
Connections
 Afferent
 Somatic and visceral
information
 Olfactory areas
 Emotional / olfactory :
amygdaloid nucleus
 Hippocampal input
via fornix – mamillary
body
 Cerebral cortex (esp.
orbital cortex
 Efferent
 Autonomic nuclei –
brainstem, spinal cord
 Striated muscle :
 Brainstem + Spinal motor
neurons (feeding /
shivering…)
 Mamillary body 
thalamus   cingulate
gyrus – memory, visceral
expression of emotion
 Mamillary body  brainstem
reticular formation
 ? Higher mental function through
cortex
Problems in Studying…
 Indistinct nuclear boundaries
 Tracts and nuclei – crisscross
 Imprecise experimental / clinical lesions
Some Functional Correlations
 Clinical / experimental
 Anterior / preoptic
: parasympathetic
 Posterior / lateral : sympathetic
 Temperature sensors – vasodilation and sweating OR
constriction and shivering.
 Hunger and satiety centres : blood glucose, visceral
afferents, smell, limbic inputs
 Intrinsic sensors
The Pituitary Connection – 1
PV
 Vasopressin (ADH)
 Oxytocin
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Large neurons (magnocellular)
Peptides and neurophysins
Herring bodies
Cleavage and release
SO
A
A
P
The Pituitary Connection – 2
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“Adenohypophysis”
Target gland hormone levels…
Small neurones (parvocellular)
Releasing factor (hormone)
Blood vessels
 Portal system
A
A
P
Summary
 Weaving together
 Autonomic and
endocrine controls
 Homeostasis
 Higher centres
Limbic System
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Limbic lobe and limbic system
“Limbus”
Lobe : hippocampus, PHG, cingulate gyrus
System : Also includes
Dentate gyrus, amygdaloid, septal area,
mamillary bodies, thalamic nuclei
Limbic System
Cingulum
and
cingulate
gyrus
Fornix
Ant nucl
thalamus
Mamillary
body
Hippocampus
Amygdala
Dentate gyrus
Parahippocampal gyrus
Hippocampus
Limbic System
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Memory
Emotion
“Preservation”
The olfactory connection
Visceral responses
Last Slide