Interacting Memory Systems Flashcards
What are the four main points of the interacting memory systems theory
- there are multiple learning and memory networks
- there are central structures that are part of a complex network (main ones being hippocampus, amygdala, and striatum)
- each system is specifically designed to represent different relationships and elements of a learning situation
- systems can interact either cooperatively or competitively to produce behaviour
competitive interaction experiment between hippocampus and dorsolateral striatum - Water Maze (Design)
3 groups: lesions of dorsolateral striatum, lesions of hippocampus, no damage
3:1 cue to place, meaning 3 days the platform is visible (cue), then 1 day (place) it is invisible in same spot. this is repeated 3 times, 12 days in total)
THEN on the 13th day the platform is moved to the directly opposite quadrant, so there is a visible platform in a completely new spot but also an invisible platform in the spot that has been trained this whole time.
competitive interaction experiment between hippocampus and dorsolateral striatum - Water Maze (Results for 3:1 (the first 12 days))
for the 3:1 cue-place learning, everything was basically equal between groups, EXCEPT hippocampus damage could not do the 4th day, the place learning
competitive interaction experiment between hippocampus and dorsolateral striatum - Water Maze
(Results of the 13th day - competition! for the CONTROL group)
control - half went to the invisible platform, half went to visible.
Noticed that rats that went to place (invisible) were better at place learning during training than the rats that went to the visible, cue
competitive interaction experiment between hippocampus and dorsolateral striatum - Water Maze
(Results of the 13th day - competition! for the Dorsolateral damage group)
became great place learners, almost all went to invisible platform.
competitive interaction experiment between hippocampus and dorsolateral striatum - Water Maze
(Results of the 13th day - competition! for the hippocampus damage group)
cannot place learn without hippocampus so went to visible platform, the cue.
What is the summary/conclusions of the competition water task of dorsolateral and hippocampal damage (3)
1.there is a balance between learning and memory systems
2.damage to one system enhances control by the intact systems
3. ABNORMAL behaviour can result from a shift in balance between systems (a system is taking control even they that arent the system that controls most in normal cases)
In the triple dissociation of memory systems, what 3 structures were involved and what tasks would they not be good at
overall it was tasks involved the radial maze
hippocampus damage = difficult at spatial task
amygdala = stimulus-reward
dorsolateral striatum = stimulus response (instrumental version)
Explain spatial variation of radial maze task
8 arms and there is food at each one. period. hippocampus damage group not good
explain stimulus response variation of radial maze task
the lit up arms have food, and 4 arms are lit up but which ones are lit change every day, therefore prevent using place learning. MUST use cue
Dorsolateral striatum damage group does not do good
explain stimulus reward variation of radial maze task
results of the 3 different version of the water maze task
hippocampus damage impaired at spatial
BUT enhanced in stimulus response (because…)
amygdala damage impaired at stimulus-reward
dorsal lateral striatum damage impaired at stimulus-response
What was an idea that mcdonald challenged from the triple dissociation radial maze task
that only one structure, ex. the hippocampus used for spatial task, is used for a specific task.
not a good conclusion because all structures are active no matter what, although the structure may not be controlling the behaviour, it is still active
What was the first challenge that mcdonald wanted to prove with the dissociation tasks
wanted to test the claim that the three tasks used were “pure” hippocampal, amygdala, and dorsal striatum tasks (meaning pure task of only hippocampal working during spatial task and other structures not even being active 0
What was the first challenge that mcdonald wanted to prove with the dissociation tasks
wanted to test the claim that the three tasks used were “pure” hippocampal, amygdala, and dorsal striatum tasks (meaning pure task of only hippocampal working during spatial task and other structures not even being active)
design procedures to asses extent of associative structure
What Question and Method was used to test the extent of associative structures (challenge 1 of the dissociation tasks)
Q = does the amygdala acquire information during acquisition of the visual discrimination task (the lit arms give a response (food))
Would train the rats to do really good on this task then do reversal learning in a different context (environment) from the orginal training context
Results of visual discrimination task and when reversed
Both groups (amygdala damage and control) did well on the visual discrimination task (getting the food because the arms are lit up)
BUT on reversal (dark arms get food), amygdala damage group took a long time to response to reversal because they amygdala is actually learning an association between light and food (which isn’t actually explicitly trained) so therefore harder to reverse
What is the amygdala learning (from the visual discrimination task when reversed, because it shows it is hard for them to respond to the reversal) experiment design
3 groups: lesions of dorsolateral striatum, lesions of amygdala, control group
training on stimulus response task (instrumental version) then do a transfer task, task they have never completed before.
Results of experiment of testing what the amygdala is actually learning
dorsolateral group performs the worst on this task, stimulus response (which is normal) - is during the testing phase
then switch to transfer phase (different task with light) and only amygdala damage group shows NO preference between arms that are light up and not. meaning that they are impaired during transfer test but still show instrumental learning
Conclusions for challenge 1 (connections of systems in dissociation tasks)
amygdala INCIDENTALLY acquires association between light cur and reinforcer during visual discrimination training.
While the dorsolateral striatum acquires a NECESSARY association between light cue and response
Now, does the hippocampus acquire information during the acquisition of visual discrimination task experiment. (what needs to be done with the controls)
and conclusion
test to make sure there is no difference between visual discrimination in different contexts of normal rats
and that they can successfully perform visual task in the first place
Conclusion = instrumental learning is not context specific
results of reversal learning in different contexts
and conclusions (for control groups)
harder to reverse in same context… even though instrumental learning is not context specific
conclusion/hypothesized that a CS-no event (no response) was associated with the not lit arms in that context
What is concluded when returning the group that was taken to a different context and reversed (for control groups only)
a competition between memory systems occurs when subjects are brought back to original training context. (because dont know whether to listen/respond more to the context compared to responding to the reversal or normal)
Results of hippocampal damage to visual discrimination task and reversal learning and competition
CONCLUSION too!
could do the visual task normally, but then when reversed, the hippocampus damage group was actually better and enhanced.
dont show competition (go back to original method and not reversed, do not do this because better at reversed)
Conclusion = hippocampus acquires the CS-no event relationship, meaning without the hippocampus the original context cannot be received
Explain what each the hippocampus, dorsal striatum, and amygdala control in the visual discrimination task
hippocampus controls the CS-no event relationship (D-)
amygdala controls reward to the light (L+)
striatum controls the response the the light (L+)
What is the different functions of the dorsal and ventral hippocampus
ventral is involved in early on and dorsal kicks in later and controls precise specificity
ventral completely drives visual discrimination task, meaning that without it, performs bad on this task
conclusion of ventral vs dorsal hippocampus in the visual discrimination task
context-specific inhibition effect is mediated by a circuit that includes the ventral but not the dorsal hippocampus
OVERALL conclusions of triple dissociation tasks
that even on the simplest learning tasks, a complex associative structure is formed in the brain.
structures are either necessary vs incidental associations
