Lectures 9 & 10 - Learning and Memory Flashcards
What is learning?
The act of acquiring new or modifying existing knowledge, behaviors, skills, etc.
What is memory?
Ability to retain and recall information, skills, etc. and is an enduring change in an organism’s function over time
What are the 3 types of memory?
- Ultra-short
- Short-term
- Long-term
What is another name for ultra-short memory?
Sensory memory
What is another name for short-term memory?
Working memory
What is an example of ultra-short memory?
Echoic memory: someone says something and it lingers for a very short period of time after it’s said
How can we expand the finite limits of our short-term memory?
Different behavioral strategies:
- Episodic buffer
- Phonological loop
- Visuospatial sketchpad
How do we make sensory memory into working memory?
Attention
What is an episodic buffer?
Remember different elements of an experience as an episode
What are the 3 phases of neural activity during working memory?
- Neural activity during cue presentation
- Neural activity during delay period
- Neural activity during response
What is a delayed anti-saccade task?
- Fixation on a point X
- Cue presentation in periphery
- Cue disappears (delay period)
- Response by looking where the cue was presented in periphery
What does the recording of one neuron response to the delayed anti-saccade test show?
A neuron responds maximally to a certain part of the visual field = spatial working memory
Where are delay responsive neurons aka short-term memory? What are they responsible for?
Dorso-lateral area of prefrontal cortex: area 46 (divided by principal sulcus)
Responsible for keeping track of the position of the flashing cue even while focusing on point X
How do we measure responses to the delayed anti-saccade test in humans? How does it work?
fMRI = indirect mechanism to measure neuronal activity
Uses differences between magnetic properties of oxygenated and deoxygenated Hb to measure neuronal activity because we know that firing neurons (aka an active area of brain) need more oxygenated blood
Which is faster: fMRI or recording neuron electrical activity?
Recording neuron electrical activity (milliseconds vs seconds)
What is temporal resolution?
Speed of test results
What is a BOLD signal?
Blood Oxygen Level Dependent signal
What do lesions to the dorsal-lateral prefrontal cortex result in?
Impaired spatial working memory
What is delay dependence of the experiments on memory?
Important control of experiments because by adding a delay the experiments show deficits have to do with memory because the deficits should get worse as the delay gets longer
If there was no delay the deficit could be due to misunderstanding of the rule, physical problem with response demanded
2 types of long-term memory?
- Declarative
2. Non-declarative
4 types of non-declarative long-term memory?
- Non-associative
- Priming
- Procedural
- Conditioning
What is non-associative long-term memory?
Discriminating relevant from non-relevant stimuli
2 other names for non-declarative long-term memory?
- Non-conscious
2. Implicit
2 types of non-associative memory?
- Habituation
2. Sensitization
What is habituation?
Diminished behavior/motor response to a repeated non-noxious stimulus
What is a non-noxious stimulus?
Stimulus that is not potentially tissue damaging
Why does habituation not happen when the repeated non-noxious stimulus’ intensity is really high?
Habituation is dependent on an ethological survival advantage, so if a stimulus signals danger that could cause damage then habituation is not possible
Describe the precise plasticity occurring during habituation.
Decrease of quantity of NT release by the sensory neuron on the postsynaptic motor neuron or interneuron and therefore same effect through the whole pathway
What is the time span of habituation?
Can last for weeks
What is sensitization?
Administration of a stimulus on another body part results in the progressive amplification of a response to a stimulus on a body part
What were the habituation and sensitization experiments done on?
Poking a sea slug’s siphon or tail and measuring the amplitude of the gill withdrawal reflex
What is the time span of sensitization?
Less than 3 weeks
What is priming?
An implicit memory effect in which exposure to one stimulus influences the response to another stimulus
What are the 3 types of specificities used in priming? Explain each.
- Stimulus specificity: effects of physical properties of stimulus between study and test (e.g. use same font)
- Associative specificity: effects of associations of target items are used between study and test
- Response specificity: effects of a change in the required response to a stimulus between the study phase and the test
What is repetition suppression? What can it explain?
Memory neural mechanism which attenuates (i.e., gradually decreases the intensity of) signals in the brain when a stimulus is detected repeatedly
Can explain priming
What is procedural memory? What are the 2 characteristics of procedural memory?
Skill learning
- Requires multiple trials
- Subjects do not know what they are learning
What is another name for procedural memory?
Implicit memory
What is an important brain structure of procedural memory?
Basal ganglia
What is the serial reaction time task?
Commonly used parameter for measuring implicit learning.
In a SRT task, participants are asked to repeatedly respond to a fixed set of stimuli in which each cue signals that a particular response (i.e., button press) needs to be made. Unbeknownst to the participant, there are probabilities governing the transition between the cues, and thus required responses following one cue have some predictability. As a result, reaction time (RTs) to these cues becomes increasingly fast as subjects learn and utilize these transition probabilities.
What patients respond poorly to the serial reaction time task?
Parkinson’s disease patients
What does a negative mean reaction time difference score mean in the SRT task?
Getting faster and faster
Why is the measured outcome of the SRT task mean reaction time difference?
You cannot compare raw motor performance between healthy and PD patients, you want to compare whether or not they will improve the speed of their reactions
What is the effect of conscious learning on implicit memory? Why?
Learning impairment
Because competition between implicit motor (basal ganglia and cerebellum) and explicit declarative (hippocampus) systems will impair learning!
Describe an experiment that shows the competition between memory systems.
Place strategy: swimming towards an exit sign (explicit strategy)
Response strategy: implicit motor function is directing the swimming
- Micro-injection of glutamate in basal ganglia increases the number of animals that adopt a response strategy
- Micro-injection of glutamate in hippocampus increases the number of animals that adopt a place strategy
- Injection of saline first favors the place strategy and after repetition of the exercise favors response strategy
Can injecting glutamate into hippocampus after a response strategy has been developed suppress it?
YUP, place strategy will be used instead
In the swim maze example, how can we tell if the animal is using place or response strategy?
Move the exit sign and see if the animal starts swimming towards where it was previously (response strategy) or where it is now (place strategy)
What are the 2 types of conditioning? Who discovered each?
- Classical conditioning (Ian Pavlov)
2. Operant conditioning (BF Skinner)
What is classical conditioning also known as?
Pavlovian conditioning
Describe classical conditioning.
Stimulus substitution where we pair a neutral stimulus (conditioned stimulus, CS) with a stimulus (unconditioned stimulus, UCS) that evokes a response (unconditioned response, UCR)
Through conditioning, the CS gains the ability to stimulate the response (conditioned response, CR)
What is extinction? Describe it in detail.
As the animal learns that the cue or context no longer predicts the coming of the unconditioned stimulus, conditioned responding gradually decreases, or extinguishes.
This is an ACTIVE process