hypothalamus and limbic system anhb 2217 – 2006 avinash bharadwaj
TRANSCRIPT
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
Column of fornix
Paraventricular
Anterior
Supraoptic
Posterior
Dorsomedial
Ventromedial
Mamillary body
Medial Zone
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
Vasopressin (ADH) Oxytocin
Large neurons (magnocellular) Peptides and neurophysins Herring bodies Cleavage and release
A
PV
SO
A P
The Pituitary Connection – 2
“Adenohypophysis” Target gland hormone levels… Small neurones (parvocellular) Releasing factor (hormone) Blood vessels
Portal systemA
A P
Summary
Weaving together Autonomic and
endocrine controls Homeostasis Higher centres
Limbic System
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
Hippocampus
Dentate gyrus
Parahippocampal gyrus
Fornix
Ant nucl thalamus
Mamillary body
Fornix
Ant nucl thalamus
Mamillary body
Cingulum and cingulate gyrus
Amygdala
Hippocampus
Limbic System
Memory Emotion “Preservation” The olfactory connection Visceral responses
Last Slide