Slide 2 Flashcards
In the monkey studies for the medial temporal lobe, where was the lesion made
bilateral medial temporal lobe
What was the task used to study the effect of a bilateral medial temporal lobe lesion in monkeys?
delayed non-matching to sample task
How was the effect of a lesion of the bilateral medial temporal lobe in monkeys measured?
performance measured at various delays
Describe the 4 steps of the delayed non-matching to sample task
- monkey moves sample object to obtain food underneath
- screen lowered in front of monkey during delay
- monkey confronted with sample object and unfamiliar object
- monkey must remember familiar object but select unfamiliar object to obtain food underneath it
IN the non-matching to sample task, what was the result for control monkeys?
delays of few mins or less: 90%
In the non-matching to sample task, what was the result for experimental monkeys (with lesions)
- short delays: normal memory
- long delays: perform at chance
What are the three major areas of the medial temporal lobe?
- hippocampus
- amygdala
- medial temporal cortex
Which part of the medial temporal lobe is very important for object recognition?
rhinal cortex
2 parts of the rhinal cortex
- entorhinal
- perirhinal
Why are delayed non-match sample tasks more precise in rats than in monkeys?
- diffs in size/location of hippocampus in rats/monkeys
- in monkeys, hippocampectomy involves removal of large part of mtl
- not necessary in rats, therefore more precise
What was used to test rats in the non-match to sample tasks?
mumby box
what three types of rats were used in the mumby box experiment?
1) control (no lesion)
2) amygdala + hippocampus
3) mtl (amygdala + hippocampus + rhinal cortex)
What was the effect on rats with a whole mtl lesion in the mumby box experiment
impaired memory
What was the effect on rats with a hippocampus + amygdala lesion in the mumby box experiment?
intact memory
What is the conclusion from the mumby box experiment?
- rhinal cortex is necessary for object recognition
- hippocampus + amygdala is not necessary for object recognition
Why must one be cautious when analyzing data from a subject like HM?
- other MTL structures are involved in memory
- not only hippocampus
What is spatial memory
memory for where things are in the environment
What is the rat experiment for spatial memory?
Morris Water Maze
Which brain area plays a critical role in remembering spatial locations and navigating through space?
hippocampus
What does the hippocampus use to represent spatial information
-place cells
What are place cells?
neurons which fire preferentially when animal is in specific locations
Who ‘discovered’ place cells?
John O’Keefe
Which animals have a larger hippocampi?
food-caching birds
What were the results of the London Cab Driver experiment?
-cab drivers had larger hippocampi
(posterior)
-recalling routes around London activates hippocampus
Why were HM’s older memories intact while he had amnesia for things that happened 2-3 years before?
- hippocampus is involved in the consolidation of memories over time
- it is not where memories are stored permanently
- hippocampus more responsible for recent memories
What brain areas are responsible for long term storage?
cortical areas
