Neuro2 Epp Learning and Memory Flashcards
Define Learning and Memory
Learning = Process to acquire memory
Memory = Behavioral change based on experience
What is synaptic plasticity?
Change in synaptic strength
What is Hebb’s postulate?
If 2 neurons that fire at the same time (within a short time frame), the postsynaptic neuron undergoes metabolic changes that increase the efficiency of presynaptic neuron
This is also called Long Term Potentiation
ie. Cells that wire together fire together
Describe Long Term Potentiation.
The strengthening of a synapse due to coordinated activity of 2 neurons
If downstream neuron fires within 20ms of upstream fire, LTP happens. If downstream neuron fires first, LDP occurs
What model systems can be used to model memory?
Primates - highly complex memory
rodents - also complex, especially spatial memory
avians - complex memory distinction
aplysia/drosophila/zebrafish - simple systems applicable for molecular work
Describe 3 types of memory based on time span and capacity.
Sensory - transient sensory input to short term (<1 sec)
Short term - Working memory, held during info processing (few mins)
Long term - possibly permanent storage of info
What are the subtypes of long term memory?
Recent and remote memory
Describe Ribot’s law and Jost’s law
Ribot’s law: old memories are less vulnerable to disruption than new one
Jost’s law: If 2 memories are of the same strength but different ages, older memory decays slower
What are characteristics of a sensory memory?
Ability to retain sensory info after stimulus ends, while it is being transferred to short term/working memory
Requires attention but not conscious awareness
Compare and contrast short term and working memory.
Often used interchangeably, but could be differentiated
short term: transient
working : transient + manipulating the info
What is working memory?
Kept transiently to process/manipulate info in some way
Describe the working memory model
If attentive, sensory memory goes to central executive (prefrontal cortex) -> Visuospatial and phonological regions take part to convert to LTM
What are the subtypes of long term memory? Break it down further with examples.
Declarative (Explicit) and non-declarative (implicit)
Declarative -> episodic (sequence of events) and semantic (facts)
non-declarative -> procedural (how to do things), priming (repetition of info), associative (conditioned behavior), and non-associative (habits)
What are 2 types of non-associative learning?
Habituation - Reduced strength of response to stimulus over multiple exposure
Sensitization - Increased strength of response to stimulus over multiple exposure
Describe how gill withdrawal reflex in aplysia demonstrates habituation and sensitization
Stimulating the siphon withdraws the gills -> over repetition withdraws less -> habituation
Weak stim to siphon -> weak gill withdrawal -> strong stim to tail -> strong gill withdrawal -> weak stim to siphon -> strong gill withdrawal
This is due to strong activation of interneurons from tail that modulate activity of siphon sensory neurons
2 types of associative learning
Classical and operant conditioning
Describe classical conditioning
Association of neural stimulus and another stimulus that elicits a specific response, such that the neural stimulus evokes the specific response
Unconditioned stimulus and response happens naturally like food + salivation
While conditioning, unconditioned stimulus is given with an unrelated stimulus
After conditioning, unrelated stimulus becomes a conditioned stimulus (bell only) to elicit a conditioned response (salivation)
Describe operant conditioning
Modification of behaviour by reinforcement after desired response
Reinforcement - anything to strengthen behavior
Punishment - anything to weaken
Positive - addition
Negative - removal
Compare and contrast classical and operant conditioning
Stimulus before to elicit response vs stimulus after response to strengthen it
Learning as a result of association vs Learning as a result of consequence
What is vicarious learning and what brain region is involved?
Process of learning behavior through observations, not direct experience.
Frontal cortex fires during task observation and execution
What is procedural learning and what brain region is involved?
Acquisition of skill through practice
Striatum, cerebellum, basal ganglia
What makes declarative distinct from non-declarative memory?
Memory you can demonstrate knowledge of by telling
Being able to convey is important
What are the properties of episodic memory?
What, when, and where
3 components that are defined by:
- Sense of time
- Connection to self
- Ability to mentally place one self in that episodic moment (mental time travel)
Which animals show episodic-like memory and how?
Srub jays
They bury insects over different locations but only eat unrotten ones
- what: insect
- when: rotten or not
- where: different bury locations
But still lacks the component if they still recall even outside of context and not recalling only when they are in the context
Difference between retrograde and anterograde amnesia
What do they tell about a brain structure?
Retrograde = inability to recall events before lesion -> info about what the structure was doing
Anterograde = inability to form new memories -> info about what rest of brain is capable of doing
How is the hippocampus involved in memory?
It encodes memories, but is not necessarily required
memory formed before HPC lesion is destroyed after lesion but memory formed after lesion remains intact
HPC lesions destroy more recent memories but not remote -> HPC doesn’t store memory indefinitely
What is systems consolidation?
Long term reorganization of memory to solidify
Hippocampus recruits cortical network activation to strengthen it and thereby transfer the memory to the cortex
What is memory reconsolidation?
When a memory is retrieved, it becomes vulnerable to disruption but also possible to update and integrate new information.
What is memory extinction? Are memories unlearned?
Memory extinction is a decrease in memory expression due to repeated CS without US
Not unlearning but formation of inhibitory memory because there’s spontaneous recovery (ie. faster relearning if you try to recover)
What is fear generalization?
Fear incubation?
Over time, fear memory is generalized to different contexts likely due to hippocampus converting the specific contextual info to a more general schematic
Fear incubation - fear memory can become stronger as they become remote
What are the two types of memory interference?
What disease is it related to?
Interference is when a similar information hinders recalling an information
Retroactive - new information hinders recalling old info
Proactive - old info hinders recalling new info
Increased interference occurs in Alzheimer’s disease and aging
How are neurogenesis and interference related?
Neurogenesis can promote forgetting of old info via retroactive interference but allows reversal learning
What are 3 ways we can forget memory?
Encoding failure - lack of attention
Storage failure - Insufficient rehearsal and consolidation
Retrieval failure - memory inaccessible
What are 3 ways we can forget memory?
Encoding failure - lack of attention
Storage failure - Insufficient rehearsal and consolidation
Retrieval failure - memory inaccessible
