Lecture 6+7 Flashcards
How is memory classified
Temporality - time course of info storage
Nature of info stored
What is learning and memory essential
Full effective functioning and survival of humans/animals
Processes are evolutionarily conserved across species
Working memory on ‘task memory’
Specific and rigid tasks e.g. reasoning or decision making
Limited capacity space
Allows stored info to be manipulated (dynamic)
Deleted after use
Lost information cannot be retrieved
8-arm radical maze test
- Arms are baited with pieces of food
- Animals free to explore arms but must remember which arms have already been visited
- Information is of no value after task completed
- Memory is reset for next task
Short term memory (ms to minutes)
- Information stored, but not always manipulated
- Only holds 7 items
- Data rich, but not suitable to store all info
- Selectively transfers to long term memory
Explicit/declarative memory
- Conscious memory
- Episodic (events) and semantic (facts)
- Flexible - multiple pieces of information associated under different circumstances
Implicit memory (Nondeclarative)
- Unconscious memory/automatic
- Inflexible - tightly connected to conditions under which learning occurred e.g. learning how to do something
Types of non-associative implicit memory
Habituation:
- Repeated exposure of a stimulus that isn’t relevant
- Important to suppress irrelevant or misleading info
- Active process, not passive loss of activity
Sensitisation:
- Enhancing response to key stimuli
- Important to focus on relevant information
- Example is cocktail party phenomenon e.g. someone mentioning your name in a conservation
Neural model of classical conditioning
unconditioned stimulus - Puff of air to eye -> detected by neuron in somatosensory system -> signal sent to synapse P (strong) -> Blink
Conditioned stimulus -> 1000-Hz tone -> detected by neuron in auditory system -> sends signal to synapse T (weak) -> Blink
Operant conditioning and associated experiment
- Trial and error learning
- Learning occurs when random activity is paired with a reinforcer (positive and negative)
- Performing complex behaviour e.g. pulling a lever becomes paired with a positive reinforcer e.g. food or with a negative reinforcer e.g. loud noise, bright light etc
Experiment for Operant conditioning
Uses mice in an operant box
Operant box contains red and green signal light
When signal light turns green, mouse pulls a lever to release food from a pellet dispenser (positive reinforcer)
If mouse pulls the lever when signal light is still red, a loud noise from a speaker will play (negative reinforcer)
The 5-choice serial reaction time task
- There are 5 holes in which one will light up at a time
- If the rat chooses the correct hole within a particular time frame, then they will recieve a reward of food
- If they poke their head in the incorrect hole, then they do not receive a reward
- If they do not poke their head into any hole, it is recorded as a missed trial
Name the 4 known and possible extra stages of explicit learning
- Encoding - Pay attention to relevant details and link it with an established memory (influenced by motivation)
- Storage - Neural mechanisms by which memory is retained over time
- Consolidation - Temporary/liable information becomes more stable
New gene/protein expression, and synapses change structure
Newer concept of consolidation of long-term memory into neural systems - retrieval - Retrieve stored information
Possible stage 5 is Re-consolidation - Once recalled information is actively liable and can be altered slightly
Henry Gustav Molaison
- Memory is a cerebral function separate from other cognitive/perceptual functions
- Medial Temporal Lobe (hippocampus, amygdala, adjacent parahippocampal cortex) play role in memory formation
Patient H.M has uncontrollable temporal lobe epilepsy caused by bilateral lesions of temporal lobes
Problems Patient H.M presented
IQ, working memory, semantic memory were all intact
No evidence of retrograde amnesia
Intact motor skills but forgets what he’d done the day before
Devastating and specific anterograde amnesia - memory lasts a few minutes and short-term memories not converted to long-term ones
Explain what different areas of the brain are involved in
- Neocortex important for long-term memory storage
- Specialised for visual tasks
- cortical areas involved in visual processing (object or spatial information processing), are seat of long-term visual memory
What is the prefrontal cortex function
Excessive function, working memory and memory retrieval
What is the parietal lobe function
Navigation
What is the cerebellum function
Motor memory
What is the occipital lobe function
Visual processing
What is the temporal lobe function
Hippocampus - Memory encoding, consolidation and retrieval
Amygdala - Emotional memory
Morris water maze
Simple spatial task that avoids olfactory cues in maze
Animals trained to find submerged platform to escape water
External cues used for navigation
Time to find platform is recorded (latency)
Length of swim path is measured (Distance analysed by video tracker system)
Platform taken out of maze to find where mouse is searching
If memory formed, animals spend more time in quadrant where platform used to be
Impaired in rats with hippocampal lesions and in mice with B-amyloid
