Download HYPOTHALAMUS I. FUNCTIONS A. Direct control of autonomic

HYPOTHALAMUS
I.
FUNCTIONS
A. Direct control of autonomic nervous system  visceromotor behaviors
i. Anterior/medial regions  parasympathetic effects
ii. Posterior/lateral regions  sympathetic effects
iii. Thermodetectors, chemoreceptors
iv. Regulation of micturition, defecation (motor centers in medullary reticular formation)
B. Hormonal control of pituitary system  regulate endocrine levels
i. Release/release-inhibiting factors in arcuate nucleus, receptors for many circulating hormones  homeostatic control of
pituitary hormones (LH, FSH, ACTH, TSH)
ii. Osmoreceptors  vasopressin (ADH); oxytocin to mammary gland
iii. Gonadal hormones  in utero morphological differentiation (anatomy, behavior, hormones, *brain organization)
*MPN larger in males, VMN in females  regulates sexual behavior
C. Communication with limbic system, midbrain  emotional experience and expression, species-preserving behaviors
i. Hunger and satiety centers (neurons sensitive to blood glucose), drinking center
ii. Circadian rhythms – sleep/wake, arousal, biological clocks
iii. Emotions: fear, rage, aversion, pleasure, reward
*also reports back to neocortex via limbic system  conveys homeostatic state
II. ORGANIZATION
A. Anterior-Posterior levels
i. Preoptic region – medial/lateral preoptic, suprachiasmatic nuclei
ii. Anterior region – paraventricular, anterior, supraoptic nuclei
iii. Tuberal region – dorsomedial, ventromedial, arcuate nuclei
iv. Posterior region – posterior nucleus, mamillary body
B. Medial-Lateral zones
i. Periventricular zone – periventricular, paraventricular, arcuate nuclei
ii. Medial zone – MPN, SCN; AN; DM, VM; PN, MMB
iii. Lateral zone – lateral hypothalamic area, LPN, SON
III. PATHWAYS AND NUCLEI
Function
Autonomic nervous
system
Pathway
Dorsal Longitudinal
fasciculus
Afferents
Nucleus of tractus solitarius 
parabrachial nucleus
(taste, pain, general visceral
sensation)
Nuclei
Periventricular
Posterior
Pituitary Endocrine
function
Supraopticohypophyseal tract
Receptors responsive to
physiological state – feedback
Paraventricular
Supraoptic
(magnocellular)
Arcuate
(parvocellular)
Retinal ganglion cells
(melanopsin – respons to light)
 optic tract fibers
LMA incl VTA (info on speciespreserving behaviors,
rewarding properties of behav)
Periaqueductal gray of LMA
(info abt pain, aversive stimuli)
Suprachiasmatic
Hippocampus
Amygdala basal forebrain
Amygdala
MMB and LHA
LHA
Periventricular
Periventricular
Tuberoinfundibular
tract
Circadian Rhythms
Retinohypothalamic
fibers
Species-preserving
behaviors
*Hypothal motivates,
limbic system selects
among them
Medial forebrain bundle
(MFB)
Connections with
higher cortex – limbic
system and prefrontal
cortex
1)Fornix
2)Ventral amygdalofug
3)Stria terminalis
4) diffuse fibers
Mammillary peduncle
(MP)
5)mammilothal tract
6)MFB
Basal forebrain
LHA
Ventromedial
Mammillary
bodies
Mammillary bodies
Entire hypothal
Efferents
Midbrain central gray
Ventral tegmental area (DA)
Medulla, autonomic centers
Brainstem
Sympathetic and paras of spinal
cord = hypothalamo-spinal tract
Supraoptico-hypophyseal tract
 post. pituitary capillaries (rel
ADH, OXT)
Tuberoinfundibular tract 
Median eminence  hypophys
portal vein (release/rel-inhib
factors to anterior pituitary)
Endogenous oscillator in SCN 
normal circadian rhythms, reset
by retinal input (normal24.5 hrs)
Basal forebrain area, picks up
fibers from LHA  limbic
midbrain areas
Midbrain reticular formation
Significance of events
Amgydala - signif of visc-sens
Amygdala
MD, intralam nuc (thal)  ant
cing cx, prefrontal
Ant thal nuc entire cing cx
Telencephalic , midbrain limbic