Lecture 16 - Learning & Memory Flashcards
Why are learning and memory important?
To be able to adapt to changes in the environment
Learning
Acquire and process information from the environment.
- Changes the nervous system
Memory
Ability to retain this information.
Hypothesized Memory Processes
3 breakdowns:
- Encoding
ex: forgetting a name after hearing it
or
ex: someone distracting you during lect & you miss what is said (not in STM) - Consolidation
ex: asked to hear name & is in STM, but didn’t study it/rehearse it - Retrieval
ex: payed attention in STS & studied in LTM, but at test got retrieval problem
- tip of tongue
- can’t get it when you need it
Multiple Trace Hypothesis of Memory
- memory is always changing
- dependent on your interpretation of the events
LTM - b/c of rehearsal, b/c of studying, it can store a lot of mem for a long time
ITM & STM - smaller capacity - last longer
Sensory buffer - dies a way v. quickly unless you pay attention to that info
Multiple Memory Systems Hypothesis
Memory can be divided into categories that reflect the type of information being remembered.
Each system primarily employs a distinct brain region.
Declarative –> Hippocampus
Procedural –> Basal Ganglia
Emotional –> Amygdala
‘Working With’ Memory –> Prefrontal Cortex
Sensory memory
Large capacity, but rapid decay.
Sensory association areas involved.
Example: Your mother is lecturing you and you aren’t paying attention, however, if asked, you can repeat the last sentence she said. (b/c still on sensory buffer)
Short-term memory(Working memory)
Lasts for seconds to minutes. (encoded)
Severely limited capacity.
magical 7 ± 2 – digits, letters, etc. (ex: phone #)
Available to conscious awareness. - aware that you have this in STM & you can use it
Prefrontal cortex involved.
Example: remember a phone number. between looking it up and dialing.
Intermediate-term Memory
Lasts for hours and days.
May be transferred to LTM through rehearsal.
Example: remembering where you parked your car.
STM and Forgetting
Decay theory
memory fades away with time, unless there is rehearsal.
STM and Forgetting
Interference theory
memory for other material interferes with information we are trying to remember.
ex: studying 3 diff courses & piles on
- new stuff can interfere with what you’re trying to rmbr
Decay Theory of Forgetting
memory fades away with time.
unless there is rehearsal.
Example: reviewing notes after class.
Interference Theory of Forgetting
Better recall when presentation of information is spaced.
Example: studying versus cramming.
Interference Theory of Forgetting
Better recall for items presented first (primacy) and last (recency) in a list.
Mechanisms of Primacy and Recency
Primacy:
Memory system has enough resources to transfer items at the beginning of a list into LTM.
Mechanisms of Primacy and Recency
Recency:
Items at the end of the list are still in STM and are therefore available for recall.
Factors Affecting Primacy and Recency
A distractor task at the end of a list interfered with recency, but not primacy.
- Interrupts rehearsal.
A faster presentation rate interfered with primacy, but not recency.
- Increases load and effects transfer of information from STM to LTM.
Changing the length of delay between training and testing interfered with both primacy and recency.
Consolidation
Hippocampus and amygdala involved.
Memories are subject to modification during reactivation and reconsolidation.
Memories are more likely to reflect how person perceived the event, rather than what actually happened.
- Confidence is not correlated with accuracy.
- Implications for eyewitness accounts, repressed memories of abuse.
Learning and memory involves multiple
processes, traces and systems.
Processes
Encoding, consolidation and retrieval.
Traces
Sensory, short-, intermediate- and long-term.
Systems
Declarative, procedural, emotional, ‘working-with’.
Long-term memory
Declarative
- Episodic
- Semantic
Non-declarative
- Procedural
- Perceptual
- Conditioning
- Non-associative
Lasts for months and years.
Takes a long time to consolidate.
Declarative memory
Knowledge we have conscious access to.
Often referred to as EXPLICIT MEMORY.
Declarative memory
Episodic
Personal experiences / events etc.
- Canoeing on Lake Winnipeg, surfing in San Diego.
Often referred to as AUTOBIOGRAPHICAL MEMORY.
Declarative memory
Semantic
Conceptual knowledge
- “Where is Lake Winnipeg, where is San Diego?”
- “How do you canoe, how do you surf?”
Classical Conditioning
association between STIMULUS-STIMULUS.
hippocampus is involved.
Unconditioned stimulus (US) stimulus (puff of air) that produces UR.
Unconditional response (UR) reflex (eye blink) to US.
Conditional stimulus (CS) an arbitrary stimulus (tone) paired closely in time with an US.
Conditioned response (CR) behaviour (blinking) now occurs in response to CS (without need for US).
Classical Conditioning
How general is this effect?
dog salivates to sounds similar to og stimulus –> generalization but doesn’t persist b/c learns to discriminate b/c gets food only during og
- if she hears bell without receiving food she’ll stop salivating to the bell
- after some time passing, when she hears again she’ll salivate – spontaneous recovery
Mechanism for Classical Conditioning: Hebbian learning
If a synaptic connection is repeatedly active at the same time a post-synaptic neuron fires, then this will lead to changes in the structure or chemistry that strengthen the connection.
Non-declarative Memory
Performance informed by IMPLICIT knowledge.
Perceptual memory
- Priming
Procedural memory
- Operant / instrumental conditioning
Emotional memory
- Conditioned fear response
Non-associative memory
- Habituation / sensitization
Perceptual Memory: Priming
An alteration of response to a stimulus as a result of prior exposure.
Can last for hours.
Not dependent on level of processing.
Reduced (but not eliminated) when presentation and test modalities are different.
Perceptual short-term memory involves the sensory association cortices.
Procedural Memory: Instrumental / Operant Conditioning
Pressing a button provides a reward.
- Increases the likelihood that the animal will press the button again.
Association between STIMULUS-RESPONSE.
- Stimuli following a behaviour can be either:
- Reinforcing: perceived as positive.
- Punishing: perceived as negative.
- Basal ganglia are involved.
Procedural Memory: Motor Learning
Series of connected movements that become automatic with practice.
Other examples: how to tie a shoe lace, ride a bike, drive a manual transmission, play piano.
Emotional Memory: Conditioned Fear
- Association between stimulus-valence (pleasant-unpleasant).
- Amygdala is involved.
Little Albert
- Conditioned to fear rats – hammer hitting metal.
- Extended to other furry animals and objects.
Nothing lasts forever!
- If CS is repeated without US often enough, then the CR disappears (EXTINCTION).
Non-associative Memory: Habituation
- Ignore incoming information that is not relevant.
- Most basic form of learning.
- Even worms can do it.
- Tap response (C. elegans)
Memory can be subdivided into multiple categories
involve distinct brain regions.
Short-term memory
Prefrontal cortex, sensory association areas
Declarative long-term memory
Hippocampus
Procedural long-term memory
Basal ganglia, motor association areas, cerebellum
Emotional long-term memory
Amygdala
Long-term potentiation
A long-term increase in the excitability of a neuron to a particular synaptic input caused by repeated high-frequency activity of that input.
- EPSP’s are summated as successive EPSP’s occur and before past EPSP’s have dissipated.
Synaptic plasticity
LTP strengthens existing synapses and creates new ones.
Important for recovery of function post stroke.
Take Home Message
Memory is multifaceted.
- Many processes, traces, systems and brain regions involved.
In classical conditioning, an organism
A) learns the consequences of a specific behavior.
B) identifies and categorizes objects.
C) shows a species-typical behavior in response to a previously unimportant stimulus.
D) is able to recognize objects by the sounds they make.
E) forms an association between a response and a stimulus.
C) shows a species-typical behavior in response to a previously unimportant stimulus.
You are listening to a song on the radio while doing your homework. The phone rings. Your mother has called to tell you that your favorite uncle has died after being hit by a car. Three months later, you again hear the same song and suddenly feel very sad. In this example, the unconditional response is
A) the voice of your mother as she relays the bad news.
B) listening to the song.
C) your feeling about the song prior to the phone call.
D) your feeling about your uncle before he died.
E) feeling sad when your mother calls with the bad news.
E) feeling sad when your mother calls with the bad news. (UR)
The \_\_\_\_\_\_\_\_ states that a weak synapse will be strengthened if its activation occurs at the same time that the postsynaptic neuron fires. A) perforant path hypothesis B) law of effect C) all-or-none principle D) Hebb rule E) law of summation
D) Hebb rule
The ability to recall a series of events is referred to as A) serial memory. B) spatial learning. C) perceptual learning. D) episodic learning. E) observational learning.
D) episodic learning.
Intense electrical stimulation of axons within the hippocampal formation results in
A) long-term potentiation of postsynaptic neurons.
B) axoaxonic inhibition of presynaptic neurons.
C) recurrent inhibition of the stimulated axons.
D) long-term potentiation of presynaptic neurons.
E) B and C are correct.
A) long-term potentiation of postsynaptic neurons.
