The Corticolimbic Circuit: Anatomy Flashcards
(52 cards)
two main functions of the corticolimbic circuit?
reaction and recognition
input to amygdala
- thalamus
- sensory cortices (which receive information from the thalamus)
what kind of information does the thalamus provide to the amygdala?
low-resolution sensory information
what kind of information do the sensory cortices provide to the amygdala?
high-resolution sensory information
output of amygdala
hypothalamus
brainstem
substantia innominata
insula
hippocampal formation
PFC
general amygdala info
bilateral in structure and function
deep subcortical structure
13 different amygdala nuclei
parts of amygdala
(input) –> BLA –> ICMs –> CeA –> (output)
Thalamus in relation to amgydala
input from the world & sends information to the amygdala BLA
parts of thalamus
ventral posterior (touch/ taste)
medial geniculate nucleus (hear)
lateral geniculate and pulvinar (vision)
what about smell and the thalamus?
smell is separate, it doesn’t go through the thalamus but straight from olfactory bulb to BLA
visual information from the thalamus
magnocellular layers of the pulvinar get information from the rods (dorsal pathway) –> “where”
cones (ventral stream) are for the sensory cortex –> “what”
high vs. low road
low road: faster processing, but more crude, motive movement
high road: what/ where
* better that low road is faster bc its more adaptive (more cautious)
example of high vs. low road
if walking on trail and see something long in the distance, may initially think its a snake and act accordingly, but quickly realize its a stick (but if it was a snake, you would have been safe)
better to look like a fool nc its a stick than risk getting bit by a copperhead
white matter pathways & recognition speed
more white matter pathways between the pulvinar and amygdala increases the speed in recognizing something as a threat or not a threat
hypothalamus and amygdala
output (HPA stress response axis)
HPA access stress response
- central nucleus of amygdala
- PVN of hypothalamus
- anterior lobe of pituitary
- ACTH
- adrenal gland
- (which stimulates response of hormone cortisol to bloodstream)
—–> which goes back and influences PVN again
stress response implications
- more glucose production in the liver
- more blood flow
- greater vasoconstriction (less bleeding)
- immune suppression
chronic stress
bad bc immune suppression normal stress response, can be really damaging
how to minimize stress output?
interesting study over impact of oxytocin
- there are oxytocin receptors on the lateral division of the CeA that can inhibit stress output
brainstem and amygdala
(output) sympathetic arousal
targets the sympathetic nervous system and increases arousal to meet immediate challenges
parts of brainstem
- midbrain
- pons
- medulla
midbrain parts
periaqueductal gray – “freeze response”
dorsal raphe nucleus – “release of serotonin”
ventral tegmental area – “release of dopamine”
neuromodulators
(dorsal raphe nucleus, ventral tegmental area, locus coeruleus)
because modulate activity in amygdala by releasing hormones
pons parts
(NRPC) nucleus reticularis pontis caudalis – “increase startle response”
parabrachial nucleus – “increase breathing rate”
locus coeruleus – “increase serotonin”
