Learning and Memory (Lecture 9) Flashcards
learning=
acquiring new knowledge, behaviors, or skills
explicit memories
declarative, things you can describe
implicit memories
non-declaractive, things learned through experience
explicit: episodic memories
events
explicit: semantic
facts
short-term memory
minutes to hours
what did you have for dinner last night?
long-term memory
relatively permanent (not forgotten) (what did you do after high school graduation?)
working memory
temporary storgage with limited capacity which requires rehearsal
(what’s your number?)
engram (or memory trace)
physical representation or location of a memory
Karl Lashley
examined the effects of brain lesions on performing a maze task
important contribution: memories are distributed
severity of deficits caused by lesions correlated with _____ of lesion… not _____.
size… not location
Donald Hebb
memories are stored in widely-distributed cell assemblies. these cell assemblies may involve many neurons (100-1000s) that are linked by synapses strengthened whenever activated together (i.e. learning)
Hebb’s theory
if an engram is based on input from only one sensory modality, it should be possible to localize it within cortex devoted to that sense
Wilder Penfield
canadian neurosurgeon “Montreal procedure”, electrical stimulation of the temporal lobe occasionally produced auditory hallucinations or recollections of past experiences (similar phenomenon during seizures of the temporal lobe)
H.M. (Henry Gustav Molaison)
underwent medial temporal lobectomy (including most underlying hippocampus) to control seizure disorder, seizures stopped but partial retrograde amnesia and extreme anterograde amnesia
what we can learn from the H.M. case:
- medial temporal lobes are involved in memory
- short-term and long-term memory are mediated by different brain structures
- declarative and procedural memory are mediated by different brain structures
- memory may exist but not consciously recalled
delayed non-matching to sample study:
tests recognition memory. monkeys must displace NEW object to uncover food. as delays increased, lesioned animals showed worse performance
what we can learn from delayed non-matching to sample:
medial temporal lobe structures important for forming (consolidating) declarative memories!
______ cortex is integral in object recognition
rhinal
bilateral removal of the RHINAL CORTEX results in:
object-recognition deficits
bilateral removal of the HIPPOCAMPUS results in:
no or moderate effects on object recognition
bilateral removal of the AMYGDALA has:
no effect on object recognition
Morris Water Maze goal:
to test the hippocampus importance in spatial memory, (rats swim the maze searching for a hidden platform and after learning where the platform is, they swim straight there)
in the Morris Water Maze: rats with bilateral hippocampal damage:
do not learn or remember location of platform
