Hypothalamus

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Hypothalamus
Rob Contreras, Ph.D. 018 Longmire contreras_at_psy.fs
u.edu 644-1751
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Historical Perspective

• Wilhelm His (1893)
• Distinct division of diencephalon
• Harvey Cushing (1920s), neurosurgeon
• Diabetes insipidus excess water excretion
  thirst
• Cushing syndrome excess secretion of cortisol
• 1930s cytoarchitectural definition of nuclei
• Functional specialization (Ranson, Hess)
• Lesion, electrical stimulation, affect appetite,
  body weight, water balance, autonomic control,
  reproductive function, emotional behavior

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Historical Perspective

• Ernst Berta Scharrer (1940) first evidence of
  neurosecretary neurons (neurons in the brain that
  secrete hormones into blood stream)
• Wolfgang Bargmann (1949) secretory neurons, cell
  bodies in hypothalamus axons in posterior
  pituitary
• Harris Green (1950s) neurohumoral regulation
  of anterior pituitary identified neurovascular
  link, portal plexus
• Guillemin Schally (1970s) characterized
  peptide hormones that act on anterior pituitary

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Cushing Syndrome
Adrenal cortex secretes too much
cortisol. Results from tumor in pituitary or
adrenal cortex. Cortisol causes proteins to break
down. Muscle atrophy, skin thinner, bones stop
growing easily fractured, lymphatic tissue
shrinks -reduced resistance to infection, fat
redistributed from arm legs to face trunk
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Olfactory input

• Multi-synaptic pathways
• olfactory tubercle, piriform cortex, amygdala
• Medial forebrain bundle
• Stria terminalis
• Ventral amygdalofugal pathway
• Fornix
• Reproduction, defense, feeding

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Visual input

• Impose temporal organization
• SCN
• Central visual projection
• Direct projection from ganglion neurons of retina
• SCN outputs sparse, confined largely to
  hypothalamic structures

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Visceral input

• Nucleus of the Solitary tract (NST), or nucleus
  tractus solitarius (NTS)
• Principal visceral sensory nucleus, input from
  major organs via VII, IX, X
• Taste, GI, cardiovascular, respiratory
• Direct to PVN, LH
• Indirect via ventralateral medulla
  parabrachial nucleus of pons

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Multi-modal brainstem afferents

• Medial forebrain bundle (bidirectional) major
  conduit
• Monoamine containing neurons
• Locus Coeruleus lateral tegmental cell groups
  (NE)
• Brainstem raphe (5-HT)
• Dopaminergic neurons
• Substantia nigra ventral tegmental area
• Former - movement latter - motivation, addiction

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Limbic inputs

• Hippocampus via fornix
• Subicular complex to mamillary bodies
  (postcomissural fornix) direct route
• Hippocampus proper (Ammons horn) via septum to
  all longitudinal levels of hypothalamus
• Amygdala
• Stria terminalis
• Vental amygdalofugal pathway

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Non-synaptic input

• Circumventricular organs
• Subfornical organ, SFO vascular organ of the
  lamina terminalis, OVLT median eminence, ME
  posterior pituitary pineal gland subcommissural
  organ, SCO area postrema, AP.
• OVLT, ME, PP in hypothalamus
• SFO AP have extensive connections with
  hypothalamus

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