Chp 12 - GOOD Flashcards
Arousing events are better remembered than non-arousing, why?
because they activate neural and hormonal processes that influence cellular-molecular processes that consolidate memories
what are the four assumptions of the memory modulation framework
- 2 independent effects of experience = initiate acquisition and storage of memory and experience also activates the release of hormones that modulate storage processes
- memory modulators are hormonal and neural systems that are not directly apart of the storage system, but influence synapses that store memory
- memory modulators have a timed role, only can influence storage of recently acquired memories when still being consolidated
- neural systems are not necessary for retrieval of memories, but are apart of modulating them
Passive avoidance task experiment in relation to memory modulators
if animal step down from platform shocked, the rats fed immediately after stepping down and receiving shock in their home cages. these rats performed better in the task and remained on the platform longer
food = time sensitive memory modulator
define memory consolidation
a hypothetical process in which the representation of a memory exists immediately after it is formed, changes over time into a relatively permanent representation (because less flexible over time)
What structure is the great modulator and why
basolateral amygdala
it is the prime modulator of epinephrine and its influence on memory
** because it connections with many regions that control storage of memory and therefore in a position to influence memory storage processes
IS NOT itself a storage site
Epinephrine roles in memory modulation
arousing event stimulates the adrenal medulla which secretes epinephrine. epinephrine mobilizes/ excites us to respond to behaviour and also influences the strength of the memory trace. epinephrine binds to adrenergic receptors
Experiments to support basolateral amygdala as great modulator
experiments to support is it not necessary for retrieval of memory.
both place learning and visible platform versions of water task can be learned and memories retrieved without amygdala, therefore isn’t necessary for retrieval and not critical storage site
hippocampus is key storage structure for place learning
effects of injecting lidocaine on basolateral amygdala
injection of lidocaine in basolateral amygdala following avoidance training impaired retention of memory/ experiment (because influences storage sites)
while injection to central nucleus of amygdala had not affect on retention
two components of adrenal gland
adrenal medulla - secretes epinephrine
adrenal cortex - secretes glucocorticoids
epinephrine plays major role in memory modulation, but what is the difficulty/problem with it
it is in the blood and too large to cross the blood brain barrier
what are the two ways in which epinephrine can move considering it can’t cross the blood brain barrier
parallel processes of both ways occurring 1. cranial nerve
2. the liver
How does epinephrine effect memory through the cranial nerve pathway
epinephrine released into blood stream from adrenal medulla. It binds to adrenergic receptors on the vagus (major cranial nerve). the vagus nerve releases glutamate onto the neurons in the solitary tract nucleus. The activated NTS releases glutamate onto neurons in the locus coeruleus which releases norepinephrine that binds to adrenergic receptors in the basolateral amygdala.
(disrupting any component prevent arousal from enhancing memory)
it sends information from all about the body to the brain
what is microdialysis used for and how does it work
this methodology is used to extract norepinephrine from the extracellular brain fluid
rat with specially designed microdialysis probe implanted into brain, rat moves freely connected to the instrument and extract small quantity of extracellular fluid and then analyzed
how are the levels of norepinephrine altered or determined when using the microdialysis methodology (3)
- levels of nore determined by intensity of shock when performing inhibitory avoidance training
- just shocking OR only explore do not increase nore levels
- requires BOTH to explore and shock for increases nore levels
locus coeruleus releases ____ into the amygdala which does what to memory
releases norepinephrine into the amygdala which enhances memory storage
what experiments provide evidence of norepinephrine enhancing memory storage
injection of norepinephrine into amygdala following place learning enhanced rats retention of platform location
when propranolol injected, impaired norepinephrine effects
What other effects does the basolateral amygdala signal do
has downstream effects, the activity produced in the BLA by the inhibitory avoidance training modulates the level of Arc protein in another area of the brain, the hippocampus. the level of Arc protein correlates with the strength of the memory
also when injected with lidocaine, inactivates neurons and reduced memory and level of Arc
how does epinephrine get released through the liver
arousing event activates adrenal medulla to release epinephrine into the blood system then it binds to adrenergic receptors in the liver. the liver then secretes glucose into the blood where it enters the brain by the cerebral vasculature system
systemic injections of what two things can influence and increase memory strength in a dose-dependent manner
epinephrine or glucose
what are the differences seen in glucose and epinephrine levels in rats of different ages
footshock causes both to release epinephrine
liver of only young rats secretes glucose (injection of glucose in old rats prevents forgetting)
requires CREB factor for enduring memories which does not occur in old rats, only with inject of glucose is CREB detected
What are the four experiments that McDonald performed to test if amygdala is a great modulator
not having it should impact the strength of memories (long term memory should be impacted without it)
1. water maze
2. long term retention
3. one-trial place learning
4. post-training memory improvement
no effect with or without amygdala, because short term memory not affected
Mcdonald vs. McGaugh view on amygdala role in memory modulation
McGaugh is the only pathway to modulate representation of memories
McDonald - amygdala is not needed in order to activate memories, it does modulate memories, but there still are other pathways that can modulate these memories too (amygdalas dominant role is actually in classical conditioning)
