PS120 Neuropsychology Term 2 Part 1 Flashcards
Declarative memory
A form of memory that involves the (conscious) recollection of experiences and facts. These recollections can be communicated to someone else either verbally or by some other means (they can be declared)
The term explicit memory is often used as a synonym for declarative memory involves the “conscious recollection of previous experiences”
Non-declarative memory
A form of memory that does not involve conscious recollection and that cannot be described or expressed verbally (cannot be declared). The existence of the memory is demonstrated through performance (i.e by doing something)
The term implicit memory is used as a synonym for non-declarative memory
Lane changing
Lane changing is a commonly executed maneouvre
The angle-time graph shows that steering wheel movement involves two ‘phases’: a movement to the right and back to the centre (phase 1) followed by a movement to the left and back to the centre again (phase 2).
Most people are unaware that lane-changing involves a two-phase (biphasic) movement of the steering wheel, though they are quite capable of executing the maneouvre
When people are asked what kind of steering wheel movement is required they say only the first phase is needed. In a simulator participants were required to execute a lane change maneouvre without being able to obtain visual feedback about the execution. The finding was that when participants could not see the road (they were driving blind when they entered the ‘tunnel’), they did not execute both phases of the maneouvre.
Motor skills being non-declarative
This an example of the memory underlying motor skill being non-declaritive, which is to say that a person can demonstrate their knowledge through doing but is not able to consciously able to retrieve information from memory concerning what exactly it is that they actually do.
What do the findings of a non-visual lane change show?
These findings show that people can execute the first phase of the maeouvre but do not produce the second phase unless they can see where they are going. Thus, initiation of the second phase required feedback from execution of the first phase.
Anterograde amnesia
Anterograde amnesia - a serious impairment of the ability to form memories of things that occurred after the brain was damaged it is not a loss of existing memory, it is a loss of an ability to form memories. They can hold some things in their mind for a few seconds but usually for no more than a minute or so.
Henry Molaison
The most famous case study: Henry Molaison was studied for fifty years until his death in 2008. Received surgery for his severe epilepsy in 1953 involved removing the medial parts of the temporal lobe (including the hippocampus) on both sides of the brain. The hippocampus is a folded ‘terminal’ part of the cerebral cortex that lies close to the midbrain.
HM’s surgery successfully dealt with epilepsy and had little or no detectable effect on his personality, perceptual ability or intelligence. He was unable to form new memories of events in his life and new facts. This inability to remember was found to be largely confined memory as he was able to develop skill in a variety of motor taks and to retain what he had learned for many years.
HM drawing a star within a star experiment - HM was able to improve performance of the mirror tracing task and retain the improvement over an extended period, though he had no recollection on either day two or three of ever having performed the task before.
What type of memory is involved in Pavlovian learning?
Non-declarative - the memories formed in non-associative and Pavlovian learning are not ‘retrieved’ from anywhere
Why is the term procedural memory problematic?
Used inconsistently: sometimes to mean non-declarative memory generally, sometimes only memory that relates to behaviours involving procedures
Confusing when used to refer to memory underlying behaviours that do not involve these procedures
Confusing because a memory of a procedure is not a procedural memory: if you can declare knowledge of a procedure, it’s not a procedural memory
Eye-blink conditioning experiment
Every once in a while a tone sounds and then a puff of air is blown into your eye (in a delay procedure)
CR acquisition is slow
Is this all a person learns? No people, may also learn that a tone sounded before every puff.
How do we know? Ask them and they will tell you (a declarative memory was formed)
These data came from an experiment in which people were watching a movie during the procedure
Most of them had a declarative memory of the procedure, but a few did not all
They all produced CRs: a declarative memory is NOT involved in the production of CRs
In eye-blink conditioning the non-declarative memory is the change in circuitry (CS -> CR circuit)
May also acquire the declarative memory that the puff of air was preceded by a tone
If there is no declarative memory, CRs are still acquired
Declarative memory plays no role in generating the CR (also non-declarative memory plays no role in the declaration that the tone preceded the air-puff)
True or false a declarative memory of the CS-US relationship is also acquired during simulatenous and backwards conditioning procedures
True - A declarative memory of the CS-US relationship is also acquired when people experience simultaneous and backwards conditioning procedures
But no CRs are acquired: declarative knowledge is acquired, but not non-declarative knowledge
Thus learning takes place in simultaneous and backward conditioning, but it is not Pavlovian learning
Retrograde amnesia
Loss of memory about life events experienced prior to the damage and factual information acquired prior to the damage
The hippocampus
The hippocampus is an infolding of the cerebral cortex along the inner edge of the temporal lobe. It is clear that it is a folded section of cortex when viewed in coronal section. The hippocampus is a key region in AA: damage it and
long term declarative memory formation is impaired,
damage the neighboring regions and it isn’t
▪ However, damage to the hippocampus is not the only kind of
damage that leads to amnesia
Korsakoff’s syndrome
Korsakoff’s syndrome (caused by thiamine deficiency,
usually as a result of long-term alcohol abuse) results in
amnesia (both retrograde and anterograde) that affects
declarative but not non-declarative memory
Brain damage
▪ The neuropathology in Korsakoff’s syndrome is widespread,
but there is relatively little effect on the hippocampus
Regions damaged in Korsakoff’s syndrome that are responsible for
memory dysfunction are the mamillary bodies, the parts of the thalamus
to which they connect, and regions of frontal cortex
Can amnesics develop CRs? Eye-blink conditioning procedure
A delay procedure was
used with a delay interval
of 1.25 seconds
▪ A group of normal people and a group of anterograde
amnesics with hippocampal damage served as participants
▪ Results: normal
participants
acquired CRs
Conditioning in amnesics
▪ And so did the
amnesics
▪ None of the amnesics formed a declarative memory of having
undergone the procedure, all the normals did (though some
failed to notice the CS-US relationship)
Eye-blink conditioning procedure - trace conditioning
The amnesics failed to acquire CRs
Results of eye-blink conditioning experiment
▪ These results are consistent with a role for the hippocampus
in the acquisition of memories when information needs to be
retained over time
Conditioning in amnesics
▪ But the hippocampus is not needed for retention: damage to
the hippocampus does not produce retrograde amnesia in
people (no loss of existing memories) and does not abolish
CRs acquired using trace procedures in rats
▪ Retention of information about the CS over the trace interval
is needed if its relationship with the US is to be discovered
Hippocampus and cerebellar cortex damage
▪ The results indicate that the hippocampus is crucial for holding information over time during the acquisition of long term memories, particularly declarative ones, but in some
cases in non-declarative ones also
Conditioning in amnesics
▪ The hippocampus is not involved in delay conditioning, but
there is a structure that may play a similar role – the
cerebellar cortex
▪ If the cerebellar cortex is damaged, CR acquisition is no
longer possible in eye-blink conditioning and a number of
other instances of Pavlovian learning using the delay
procedure
▪ A kind of anterograde amnesia (though for a non-declarative
memory)
▪ As with the hippocampal removal, removal of relevant parts of the
cerebellar cortex do not abolish CRs that have already been acquired (no
retrograde amnesia type deficit)
Conditioning in amnesics
▪ For different types of memory, we find structures in the brain that are
involved in acquisition but not retention (other structures are involved in
retention)
▪ If the structures involved in acquisition are damaged, new longer term
memories cannot be formed (called anterograde amnesia when
declarative memories are involved) but old ones are left intact (no
memory loss)
▪ If the structures involved in retention are damaged, old memories are lost
(called retrograde amnesia when declarative memories are involved)
▪ But brain damage is not a common reason for memory loss – we will
discuss forgetting and unlearning next (in the context of Pavlovian learning)
What two circumstances are there in which people may what to undo the effects of prior learning?
▪ (1) You may want to rid yourself of a bad technique or habit
that you have acquired so that you can perform better at
some skilled behaviour (such as a sport)
▪ (2) You may want to rid yourself of an acquired irrational
fear (phobia): you may want to stop being afraid of spiders,
open spaces, confined spaces, flying, public speaking etc.
What are the two ways of actively ‘undoing’ the effects of learning?
- Erase the memory (memory is lost) or erase the means
of retrieving it – erasure - Suppress the memory or suppress the means of retrieving it (memory is still there and so is the means of retrieval, but you can’t get it/use it) - suppression
What are the two phases to undo Pavlovian conditioning?
Phase 1: training with a forward conditioning protocol in
which CS is paired with a US until learner acquires a CR
Phase 2: exposure to a sequence of presentations of the
same CS but without presentation of any USs
What is extinction procedure?
A procedure that follows conditioning and involves
presenting the CS without the US is a called an extinction
procedure
Spontaneous recovery
If the ‘memory’ had been erased, then the behaviour could
not reappear but it can. Recovery tends to be greater for longer intervals.
Renewal
▪ Observation 2: renewal
▪ The subject is conditioned in one context (e.g., a particular
room or cage – context A) and then is transferred to a
different context (B) where an extinction procedure is
administered.
▪ After extinction, the subject is either transferred back to
context A or to a completely new context (C)
▪ Back in context A (or in context C), the animal is tested with
the CS alone – it is found that conditional responding is
present again (it has been renewed)
▪ Renewal effect is stronger in the ABA context sequence
than it is in the ABC sequence
Reinstatement
▪ Following extinction, the subject is presented with an
aversive or otherwise arousing stimulus (often the US used
in training)
▪ The CS again elicits the CR
Effect of Extinction
EFFECT of EXTINCTION: extinction procedures do not
erase what has been previously learned (memories);
previous learning is retained, it just isn’t (always)
possible to express it in behaviour – it is suppressed.
Mechanism of suppression
▪ During the extinction procedure, the trainee learns to
suppress the acquired stimulus-response relationship so
that the conditional responses are no longer produced
▪ This is new learning that counteracts the effects of prior
learning
▪ The neural process that produces suppression is
inhibition, so the result of learning during extinction is
likely to be an inhibitory stimulus-response connection of
some kind
▪ The conditional reflex pathway (memory) is intact, but an
inhibitory pathway formed as a result of extinction prevents
the CR from occurring
Why suppress learning rather than erase?
A clue in the finding that extinction is context sensitive. ▪ Recall that renewal
demonstrates this
sensitivity
▪ Reinstatement also
demonstrates
context sensitivity
▪ Reinstatement occurs provided retention test is in the same
context as that of the prior experience
Context sensitive suppression of prior learning (rather than erasing it)
means that what has been learned is not completely lost, but is available in
contexts where it might still be relevant and useful
Thorndike Cat Puzzling
Observed that cats tried to squeeze through the cage and tried to bite and squeeze the wired. The measured time taken to escape from the box decreased - by the end of day 2, the cat pulls on the loop almost immediately after being placed in the box.
Box K cat puzzling
Box K was quite complex with 3 actions needed to open the
door: press down on bar, pull down on loop and press on
treadle. ▪ The cats’ behaviour changes as a result of its consequences
Instrumental learning
▪ The behaviour change consists (primarily) of two things: (1)
some behaviours become more likely over repeated
experiences, (2) some behaviours become less likely over
repeated experiences
▪ Note that no new behaviours are acquired – the cats could
already do what was necessary to escape
▪ The cats’ learning process is a kind of trial and error
learning
▪ The cat tries things out (things it can already do) and
changes its behaviour according to whether the trial is a
success or a failure (error)
Law of Effect
▪ It is important to recognise that the Law of Effect is an
hypothesis with several components
▪ It asserts that satisfaction/ dissatisfaction is evoked by
certain events (e.g., escape evokes satisfaction as does
eating)
▪ Satisfaction/dissatisfaction changes the strength of these
connections
▪ The organism has pre-existing connections between stimuli
and behaviours (responses)
▪ The organism does not have connections between
behaviours and their consequences or the satisfaction/
dissatisfaction that they evoke
S-R Theory
Situational stimuli come to elicit a single behaviour (or set of behaviours) in a reflex-like fashion.
The experienced cat does not
pull the loop in order to get out,
it does so because situational
stimuli elicit loop pulling called S-R theory
▪ According to S-R theory animals do not do things in order to
achieve specific outcomes
Reinforcement
▪ In everyday language, reinforcement has two basic
meanings: (1) the act or process of strengthening
something; (2) the thing(s) that does the strengthening
▪ In the context of learning theory, reinforcement is used in
the first sense, but not the second:
▪ The process of strengthening a ‘connection’, such as a
stimulus-response connection
▪ Something that leads to the strengthening of a connection
when it is delivered/produced as a consequence of
behaviour is called a reinforcer
Positive reinforcement
▪ Delivery or production of a stimulus item (like food) that
results in strengthening of a connection/behaviour is called
positive reinforcement
Some terminology
▪ The term ‘positive’ is used to denote the fact that something
is added or delivered to the situation (not to denote that the
reinforcer is ‘good’ or delivers a ‘positive experience’)
Negative reinforcement
A behaviour/connection can also be strengthened by
removing something from the situation – this is called
negative reinforcement
▪ Positive reinforcement is reinforcement by addition,
negative reinforcement is reinforcement by subtraction
▪ This is usually achieved by removing something aversive/
unpleasant
Punishment
Punishment: The delivery or production of a
stimulus that has punishing effects (a
punisher) as a consequence of a behaviour.
▪ Punishing effects are opposite to the effects of reinforcement:
a reduction in the likelihood of a behaviour, a decrease in its
strength/vigour and/or an increase in its latency
True or false a punisher is almost always an aversive stimulus of some sort
True
Positive punishment
▪ Positive punishment is the delivery/production of a
punishing stimulus (like a smack)
Negative punishment
Negative punishment is the removal of a desirable or
rewarding stimulus
Instrumental conditoning procedure
These procedures involve setting up an experimental situation in which executing a particular behaviour which results in the delivery of reinforcement or punishment.
What is it called when a labortatory training protocol uses only teinforcement or punishment?
Instrumental conditioning procedure or operant conditioning procedure
Thorndike R-O associations
According to Thorndike, stimuli and outcomes do not
become connected (associated) in the learner’s ‘mind’ (or
brain) and neither do responses and outcomes. The learner doesn’t acquire any knowledge about outcomes
of responses (R-O associations) or about the circumstances
in which those outcomes come about (S-O associations).
How do we prove Thorndike’s theory is not always the case in animals?
The most important body of evidence for R-O theory comes
from a technique called outcome (or reinforcer)
devaluation. The idea is a simple one: if the organism produces a
behaviour because it is motivated to obtain the outcome/
reinforcer associated with it, then decreasing motivation
should reduce the likelihood of the behaviour.
Reinforcer devaluation - rats case study Colwill & Rescorla, 1986
Rats were trained using an instrumental conditioning
procedure: a reinforcer was delivered for pushing a rod on
the right or on the left. The rats had the choice of
pushing the right or left rod: if
they pushed it to the left they
would receive a sugary reward
(sucrose solution), if they
pushed to the right they would
receive a savory food reward. The training establishes both responses: sometimes the rat
will push the left rod to drink sugary water, sometimes it will
push the right one to eat a tasty snack. Following this initial instrumental training, one of the reinforcers
was devalued using a taste/smell aversion procedure. No reinforcers were delivered in the test phase to ensure that
only what the animals had previously learned would affect
their behaviour. Reinforcer devaluation typically reduces the likelihood of a
behaviour being executed (or of otherwise reducing the
strength of a behaviour), demonstrating that the value of
the outcome affects responding. Indicates that organisms learn about response-outcome
relationships and use this ‘knowledge’ for deciding whether
or not to perform a behaviour
Why in some situations does a learned behaviour produced regardless of whether the reinforcer’s value is reduced or not?
Can happen following very extended periods of ‘training’. ▪ Habits are sometimes described as ‘over-learned’, because
it seems as though ‘too much’ learning leads to inflexible
behaviour.
Habitual behaviour
An instrumental
behaviour whose production is insensitive to the
value of its outcome or associated reinforcer
Goal-guided behaviour
an instrumental
behaviour whose production is sensitive to the
value of its outcome or associated reinforcer
Is it true that instrumental learning is just the strengthening
and weakening of S-R connections?
No, it also involves learning about response-outcome
associations (and associations between situations and
outcomes as well)
Is it true that animals do things in a reflex fashion without any
intent or aim to achieve a specific outcome? If true, are we
different? Why?
No, animals can learn to do things in order to achieve
outcomes/gain rewards (goal-guided) Extensive training/experience can lead to habitual
behaviours that are stimulus-elicited rather than goal-guided
Shaping
A method of training a response by reinforcing a sequence of progressively closer and closer approximations to a target behaviour.
Learning to change gears
We know that there is much more to learning sequential
actions like these than simply performing the correct
elements in the correct sequence
▪ A classic example is learning to change gears in a car with
a manual transmission
▪ The novice driver knows how to perform each element in
the sequence, they just need to make sure that they do
them in the right order (and with the right overlap)
▪ But novice performance is strikingly different from that of
experts in several different ways
▪ The learner is aware of having to make a conscious
decision to execute each component
▪ The learner is aware of having to make a conscious
decision to execute each component
Fluency and blending - expert/novice differences in joining dots
▪ The expert is more fluid: no pauses between elements in
well practiced sequences
▪ Elements run smoothly together and the movements/ muscle
contractions involved in their execution overlap with one
another
▪ In the novice it is typically easy to tell where the performance
of one element ends and where the next element begins
▪ In the expert the boundaries are blurred and may be
impossible to detect
What are the three stages of skill acquisition?
STAGE 1: COGNITIVE STAGE – highly attention demanding;
requires awareness of what you’re doing; use of explicit working
memory; slow
STAGE 2: Fixation Stage – components of action grouped into
‘chunks’; fewer decisions, less explicit memory demand
STAGE 3: Autonomous Stage – execution proceeds
“automatically” without thinking; no demand on explicit
working memory; low attention demand
The cerebral cortex
Like a walnut, the brain appears
to be divided into two parts
This is true for the part you can
see here and for some of the
parts you can’t see
The cerebral cortex comes in
two separate wrinkled sheets –
one on the left that forms a kind
of ‘skin’ of the left hemisphere,
and one on the right
Customary to divide the cerebral cortex on each side into
lobes
Lobes of the cerebral cortex
- Frontal lobe - the frontal lobes comprise a big chunk of the cerebral cortex
- Patietal lobe
- Occipital lobe
Where is the primary cortex (M1) located/occupying?
Precentral gyrus
Motor cortical regions
A role in motor function for most of these areas was originally
determined from the behaviour of people who had damage or
pathologies that affected them
We will see in week15 that the motor speech area (Broca’s
area) was first identified based on the effects of damage to
this area due to stroke
One exception is the primary motor cortex (M1), the motor
function of which was determined by direct electrical
stimulation of the brain surface when the head was opened
for surgery
Damage to frontal motor areas
Damage to primary motor cortex → problems coordinating
and controlling muscles in voluntary movement; tight
(contracted) musculature (hypertonia)
Damage to frontal motor areas
Damage to the more rostral motor areas does not affect
muscle control, but has effects on planning, selecting and
initiating acts and/or courses of action
For example, damage to Broca’s area does not affect the
ability to produce speech sounds, say words or to move
those parts of the body associated with speaking
It affects a person’s ability to produce comprehensible
speech – speech lacks grammatical structure and other
qualities that make the intended message understandable
(more about this in week 15)
Go from Week 2 Lecture 2&3
