limbic system

Question 1

what is called as normal, age related cognitive decline

Answer 1

many cog functions decline with age

e.g. spatial memory
e.g. spacial navigation task

e.g. long term memory, processing speed

Question 2

how does the hippocampus change/ not change in ageing

Answer 2

doesnt get smaller

retains same number of neurons

but, functional connectivity is impaired so retrieval is not as strong

long term potentiation doesnt last as long, and not as strong

impaired retrieval of spatial maps

Question 3

what is the ventricular system

Answer 3

filled with cerebrospinal fluid

shock absorber

nutrient supply

waste flush

anatomical landmark

Question 4

what/where is cerebrospinal fluid produced

Answer 4

ependymal cells that line ventricles

Question 5

common signs of alzheimer’s disease - 8

Answer 5

memory loss

poor judgement thus bad choices

loss of spontaneity/ initiative

taking longer to complete daily tasks

repeating questions

trouble handling money, paying bills

wandering, getting lost

losing things or misplacing them in odd places

Question 6

common signs of alzheimers linked to the hippocampus - 3

Answer 6

memory loss

wandering and getting lost

losing things or misplacing them in odd places

Question 7

alzheimers disease impact on brain

Answer 7

loss of neurons in regions, esp hippocampus and cerebral cortex

Question 8

alzheimers disease cause

Answer 8

accumulation of misfolded proteins in certain brain regions:

cholinergic nuclei, hippocampus and frontal cortex

accumulation is toxic - not sure why

some genetic risk

Question 9

what is the protein that misfolds most commonly in alzheimers disease and what do they form - 2

Answer 9

beta-amyloid, forming amyloid plaques

tau, forms neurofibrillary tangles

Question 10

alzheimers disease treatments - 2

Answer 10

memantine

acetylcholinesterase inhibitors - most commonly px

Question 11

memantine mechanism of action

Answer 11

slows exitotoxicity of glutamate

Question 12

acetylcholinesterase inhibitor mechanism of action

Answer 12

mitigate loss of ACh by blocking breakdown

Question 13

key parts of the brain’s cholinergic system

Answer 13

aids learning by releasing ach into hippocampus

key nuclei: basal forebrain and brainstem tegmentum

project across brain

memory, cognition, cognition arousal

Question 14

hippocampus is part of what

Answer 14

limbic system

Question 15

what is the amygdala

Answer 15

part of limbic system

fear - vigilance

thalamus talks to amygdala to determine if something is worth caring about via amydgalofugal pathway

how important it is - salience

stimulation causes fear anndd aggression

recognising fear in others

Question 16

what is the fornix

Answer 16

part of limbic system

output of limbic system, connected to mamillary body

Question 17

what is the hypothalamus

Answer 17

part of limbic system, final output of limbic system, connects to endocrine system

Question 18

clinical relevance of amygdala

Answer 18

anxiety disorders - hyperactive, hypervigilance

bilateral lesions can cause kluwer-bucy syndrome - but rare as both sides are far apart

Question 19

what is kluwer-bucy syndrome

Answer 19

reduced fear/ docility

visual agnosia

pica - putting things in ur mouf like kids

hyperorality and hypersexuality

normally caused by surgical complications

Question 20

where is the fornix

Answer 20

connects hippocampus to other structures and also left and right hippocampus

in hippocampus

hippocampal output

damage is rare, also jst looks like hippocampal damage

Question 21

mammillary body damage causes what

Answer 21

korsakoff’s syndrome:

irreversible damage to medial thalamus and mamillary bodies

caused by chronic alcoholism, unable to absorb vitamin b1/ thiamine

direct toxicity of alcohol

anteriograde and retrograde amnesia

confabulation - confusion between memory and imagination

Question 22

what does the hypothalamus do

Answer 22

hypothalamus-pituitary-adrenal HPA axis - signal to hormone

esp stress hormone output

also wired to brainstem - autonomic system

thermoregulation

hunger, thirst, etc

final output - rest of limbic system trying to persuade hypothalamus to do what the limbic system wants

Question 23

olfactory pathways and the thalamus

Answer 23

dont rly associate with the thalamus

connect to limbic and memory systems instead

Question 24

pavlovian classical conditioning

Answer 24

bell = neutral stimulus

paired bell and dog food = bell = conditioned stimulus

so dog salivates to bell = conditioned response

limbic system

Question 25

amygdala role in classical conditioning

Answer 25

amygdala important for learning conditioned cues esp danger and fear

Question 26

pavlovian classical fear conditioning

Answer 26

ptsd person has war trauma - gunfire unconditioned stimulus - fear of death, fear is unconditioned response neutral stimulus - palm trees of war environment. fear of palm trees, conditioned response

Question 27

what is forgetting also known as

Answer 27

extinction of classical conditioning learning of newer associations replacing older/ becoming more salient

Question 28

what happens in ptsd

Answer 28

"forgetting" goes wrong symptoms are normal for few weeks, longer is ptsd hyperarousal, hypervigilance, on edge avoidance of stimuli emotional numbing eventually ie person is generalising all trees, avoiding as produces fear reponse as per amygdala amygdala is winning over hippocampus, as hippocampus would otherwise acknowledge that cue in environment is normal, not cause for fear - prefrontal cortex is referee aka, amygdala is hyperactive, prefrontal cortex is smaller, hypoactive and hippocampus is smaller and has impaired function sufferer knows that something is wrong - prefrontal cortex

Question 29

treatments of ptsd

Answer 29

cbt, exposure therapy ssris to elevate mood and reduce anxiety