E3 limbic system Flashcards
3 main limbic circuits
memory with hippocampus
emotion with amygdala
reward with nucleus accumbens and ventral tegmental area
layers of hippocamups proper
3 is polymorphic layer (0utput)
2 is pyramidal layer
1 is molecular layer (deepest)
layers of dentate gyrus
3 is polymorphic (output)
2 is granular
1 is molecular (most superficial)
hippocamups internal loop
long term storage
cotical association areato to entorhinal
to dentate gyrus granule cells via perforant path
to CA3 pyramidal neuroons via mossy fiber system
to CA1 pyramidal neruans via schaffers collaterals
to subiculum and back to entorhinal and to coritcal association areas for storage
hippocampus external lop
CA3 gets input same way and again sends to CA1 and to subiculum but then from CA1 and subiculum through alveus and fornix to septum and mammilary body
then to anterior nucleus of thalamsus via mtt the n to cinulate gyrcus then to entorhinal cortex and out to cortical association for storage
long term potentiation
some handwaving about the strength of synaptic connections
happens in granule cells and pyramidal cells of CA1, CA3
basically after tetanic stimulation the same stimulus produced a greater response
hippocampus and alzheimers
CA1 hit first and worst
extracellular plaques and intracellular tangels
hippocampus and ischemia
CA1 usually gets deprived of oxygen and loses cells
hippocampus and epileptic seizures
most electrically excitable part of brain
too much glutamatergic transmission
kluver bucy syndrom
bilateral lesion of temporal lobes visual agnosia oral tendencies hypermetamorphosis emotion dulled and loss of fear hypersexuality from herpes eimplex encephalitis anterograde amneisia
korsakoffs syndrom
thiamine deficieincy
anterograde amnesia
retrograde amnesia
confabulation
3 amygdala nuclei
latearl LA for sensory input
basal B for contextual input from hippocampus
central CE output
2 output pathways of amygdala
stria terminalis to hypothalmus
vantral amygdalofugal pathway VAFP to hypothalamus and MD thalamus
short route amygdala
sensory thalamus directly to amygdala
low info but fast
long route amygdala
sensory thalamus to sensory cortex to amygdala
slow but more context
ventral tegmental area
dopaminergic
mesolimbic pathway
mesocortical pathway
mesolimbic pathway
VTA to nucleus accumbens
mesocortical pathway
VTA to prefrontal cortex
Nucleus accumbens
reward pleasure addiction
GABA ergic
inputs from PFC, amygdala, hippocampus, VTA
outputs to netral pallidium to mediodorsal nucleus of thalamus to pfc
GABA so inhibits VP so disinhibits MD which then activates PFC
cocaine exampel
dopamine reuptake inhibition tolerance dependence and withdrawal craving implicit emotional memories and cravings basically forever
HPA axis
hypothalamic pituitary adrenal axis
paraventricular nuclues
anterior pituitary gland
adrenal cortex
stress activates PVN to release corticotrophin releasing factor/hormone to tell anterior pituitary to release adrenocoritcotropin hormone which tells adrenal cortex to release glucocorticoids like cortisol
this results in anti inflammatory and immunosuppressive actions
SAM axis
sympathetic adrenal medullary axis
fight or flight
autoregulation of HPA axis
corisol has negative feedback loop on hippocampus, PVN and anterior pituitary
dysregulation of HPA axis
chronic stress
less cortisol receptors so negative feedback stops working
