Week 3 - Learning And Memory Flashcards
What did patient HM suffer from?
Refractory seizures
On 01/09/53 what did William Scoville perform on HM?
Bilateral temporal lobectomy
What are the important site for the generation of the seizures?
Amygdala
Temporal lobe
What brain regions did William Scoville perform the surgery on?
Amygdala
Entorhinal cortex
Hippocampus
What was the surgery successful in?
Treatment of epilepsy
What did HM know up until 2 years before his surgery?
Who he was How to do things Personal history Facts learned in school Language Social events People Almost everything
HM short term memory was intact, what could he no longer form?
Long term memories
What are intimately linked?
Learning and memory
What is learning?
The process of acquiring knowledge or skills through experience, study or being taught
What is memory?
The faculty by which the mind stores and remembers information
What is memory?
The outcome of learning
What is learning all about?
Changing behaviour
Improving self
It is a survival advantage
What does survival advantage of learning and memory teach?
Avoid situations that you find dangerous
Seek those that were previously beneficial
What does all form of learning and memory involve?
Cellular and circuitry changes in the nervous system
What can memory be?
Very short-lived
Short-to-medium lived
Long term
Very short lived
Sensory memory (msec-sec)
Short-to-medium lived
Short term memory and working memory (sec-min)
Long-term
Long-term memories (days-years-decades)
What are the 3 major processing stages that sustain learning and memory?
Encoding
Storage
Retrieval
What is encoding?
The processing of information that creates a memory trace for storage
What are two divisions of encoding?
Acquisition - sensory stimuli make the cut into STM
Consolidation - changes in brain stabilise memory over time resulting in LTM
What is storage?
Result of acquisition and consolidation
Represents the permanent record of information
What is retrieval?
Accessing stored information
Create conscious representation or execute a learned behaviour
What are the properties of declarative memories?
Conscious
Verbal
Holistic
Contextual
What is the key structure of the medial temporal lobe?
Hippocampus
Where does the cortical projections terminate ?
Parahippocampal cortex
What are regions associated with medial temporal lobe?
Hippocampus Entorhinal cortex Perirhinal cortex Parahippocampal cortex Mammillary bodies Anterior thalamus nuclei
Where are the medial temporal lobe and hippocampus connected through?
Fornix
When the information leaves through the fornix where does it go to?
Subcortical structures
What are the subcortical structures?
Thalamus
Mammillary bodies
Basal forebrain
What was thought previously of memory?
Could not be separated from perceptual and intellectual functions
What was HMs problem?
Purely a memory problem
What did HM have?
Normal intelligence Normal perceptions No motor dysfunction No language impairment No psychological or mental illness Normal cognitive control Normal working memory Normal short term memory Normal procedural learning
What does the extent of memory deficit depend on?
How much of the medial temporal lobe have been removed
What results in severe amnesia?
Only bilateral resection
What is digit span memory?
Store short term digits
What is the digit span for most individual?
Between 7+-2
What does reversed number decrease with?
Age
What was disrupted in HM?
Transfer of information from short-term storage to long-term memory which is disrupted
What is anterograde amnesia?
The loss of memory for events and knowledge that occur after brain damage
What is Retrograde Amnesia?
The loss of memory for events and knowledge that occurred before brain damage
What is temporal gradient or Ribots Law?
The most recent memories is lost
What things could HM and other patients with anterograde amnesia learn?
Motor skills Procedure Perceptual skills New concepts World knowledge
What does short-term memory include?
Sensory memory
Short term memory
Working memory
What is sensory memory?
The transient retention of sensory information in sensory structures
What is short term memory?
Short-term stores for information about the world
What is working memory?
Storing, focusing attention on and manipulating information for a relatively short period of time
What is the auditory verbal information presented as?
Sort of echo in head
What is Echoic memory?
Persistence of the auditory sensory memory trace
What is Iconic memory?
Persistence of the visual sensory memory trace
How can sensory memory trace be measured by?
Event-related potential (ERP)
Event-related field (ERF)
What is the event-related potential?
Measures brain response that is the direct result of a specific sensory,cognitive or motor event
What does the auditory stimuli leave in the auditory system?
A trace that affects the processing of subsequent stimuli
What is the mismatch negative a difference between?
Deviant and normal standard stimulus
How long does the memory trace of auditory stimuli last for?
9-10 seconds
What happens after 10 seconds?
The brain is free to process another secondary stimulus
What does the echoic memory have a time course of?
Around 10 seconds
What is neural trace of visual stimulus?
Only 300 to 500 msec
Sensory memory
Relatively high capacity (can retain a lot of information
For a very short period
Short term memory
A more limited capacity
Longer time course (sec to min)
Who studied the capacity of short term memory?
George Miller
What is capacity (span)?
Quantity of information can be held in memory
What is attention?
To move information from sensory to short term memory (STM)
What is rehearsal?
To move information from short term memory (STM) to long term memory (LTM)
What is retrieval?
To move information back into short-term memory (STM) from the long term memory (LTM)
What does the short-term memory store?
Approximately 7+/-2 items in an acoustic code for 15-30 seconds
What is displacement?
New information comes along and pushes the old information out
What is decay?
Information simply fade away
What is central executive?
Drives the whole system and allocated data to the subsystems
The phonological loop
Visuospatial sketchpad
Deals with cognitive task: mental arithmetic and problem solving
Manages attention
Coordinates interaction between two short term memory stores and with long term memory
What is the visuospatial sketch pad (inner ear)?
Stores and processes information in a visual or visuospatial code
What is the phonological loop?
Part of working memory
Deals with spoken or written material
What are the two parts of the phonological loop?
Phonological store (inner ear) Articulatory control process (inner voice)
What is the phonological store?
Linked to speech perception
Holds information in a speech based form (spoken words) for 1-2 seconds
Short lived acoustic store for sound input and any visually presented language converted by articulatory control process
What is the articulatory control process?
Linked to speech production
Used to rehearse and store verbal information from the phonological store
What does the visuospatial sketchpad depend on?
Integrity in both hemispheres
What does phonological loop depend on?
Integrity in left hemisphere
Lesion in either LEFT hemisphere
Lateral frontal lobe Brodmann area 44 (Broca’s area) Inferior parietal love Left supramarginal gyrus Brodmann area 40
Lesions in either RIGHT or LEFT hemisphere
deficit in visuospatial working memory
What are examples of right/left hemisphere
Anterior occipital cortex (Extrastriate cortex) Broadmann Rea 19 Inferior posterior parietal lobe Supramarginal gyrus Broadmann area 40
Where did KF suffer brain damage?
Left posterior parietal brain area from a motor cycle accident
Damaged his short term memory
What happens when there is no frontal cortex?
Information cannot be held
What requires an intact medial temporal lobe?
Acquiring new declarative memories
What was not used during HM surgery?
Ferromagnetic materials
Half of the posterior region of H.M. hippocampus was…
Intact
How much of the medial temporal lobe have been removed?
Only 5cm
What was mostly spared?
The posterior parahippocampal gyrus
What was removed?
Anterior portions of the parahippocampal gyrus
Most of the perirhinal and most or all of the entorhinal cortices
How did patient R.B lose his memory?
After an ischemic episode during heart bypass surgery (1968)
What did patient R.B have?
Dense anterograde amnesia
Mild temporal retrograde amnesia
With R.B what appeared to be intact?
Hippocampus
Where did R.B have a very specific lesion restricted to?
CA1 pyramidal cells
What is particularly vulnerable to injury?
CA1 subfield of the hippocampus
What is crucial for the formation of new long term memories?
Hippocampus
What can Amnesia be caused by?
Lesions in regions connected to, but outside of, the medial temporal lobes Stroke Tumour Trauma Metabolic problems
