Download Emotional Behaviors

PSY 335: BIOLOGICAL PSYCHOLOGY
Chapter 12:
Biology of Learning & Memory
Learning, Memory, Amnesia, and
Brain Functioning
• An early influential idea regarding localized
representations of memory in the brain suggested
physical changes occur when we learn something
new
• One popular idea was that connections grow
between areas of the brain
Localized Representations of Memory
Ivan Pavlov researched classical conditioning in
which pairing of two stimuli changes the
response to one of them
• Presentation of a conditioned stimulus (CS) is
paired with an unconditioned stimulus (UCS)
• Automatically results in an unconditioned response
(UCR).
• After several pairings, response can be elicited by
the CS without the UCS, which is known as a
conditioned response (CR)
Localized Representations of Memory
In operant conditioning, responses are followed by
reinforcement or punishment that either strengthen or
weaken a behavior
• Reinforcers are events that increase the probability that the
response will occur again
• Punishment are events that decrease the probability that the
response will occur again
Classical Conditioning 
Operant Conditioning 
Lashley’s Search for the Engram
Pavlov believed that conditioning strengthened connections
between the CS center and UCS center in the brain
Lashley (1929)
• Set out to prove this by searching for such engrams, or
physical representations of what had been learned
• Posited that a knife cut should abolish the newly learned
response
Karl Lashley
(1890-1958)
Lashley’s Search for the Engram
Lashley (1929)
• Attempted to see if disrupting certain connections between
cortical brain areas would disrupt abilities to learn
associations
• Found that learning and memory did not depend on
connections across the cortex
• Also found that learning did not depend on a single area of
the cortex
Pavlov’s view of the
physiology of learning 
Lashley’s Search for the Engram
Lashley (1929)
• Proposed two key principles about the nervous system:
• Equipotentiality – all parts of the cortex contribute equally
to complex functioning behaviors (e.g. learning)
• Mass action – the cortex works as a whole, not as solitary
isolated units.
The Modern Search for the Engram
• Modern day research by Richard F. Thompson and
colleagues has suggested that the engram for classical
conditioning is located in the cerebellum, not the cortex
Thompson (1986)
• During conditioning, changes occur in cells of one nucleus of
the cerebellum called the lateral interpositus nucleus (LIP)
• However, a change in a brain area does not necessarily
mean that learning necessarily took place in that area
The Modern Search for the Engram
• Suppression of activity in the LIP led to a condition in
which the subject displayed no previous learning
• As suppression wore off, the animal began to learn
at the same speed as animals that had no previous
training
• Increased brain activity in LIP suggests it is
essential for learning
• However, suppression of the red nucleus also led to
a similar condition
The Modern Search for the Engram
Halverson, Lee, & Freeman (2010)
• Investigated whether there could be more than one area
responsible for learning using
Procedure
• Conditioned eyeblink response to participants hooked up to
brain monitors
Results
• Classical conditioned eyeblink response lead to increased
activity in LIP and medial geniculate nucleus (MGN)
• However, the activity increased first in the LIP area
Interpretation
• Increased activity in MGN only represents feedback from LIP
• Learning itself must rely on the LIP area alone
Types of Memory
Hebb (1949)
This researcher differentiated between two types of
memory:
1. Short-term memory (STM) – memory of
events that have just occurred
2. Long-term memory LTM) – memory of events
from previous times
Types of Memory
Major Differences between STM and LTM
1. Short-term memory has a limited capacity; longterm memory does not
• Miller (1956): “The Magic Number” = 7 +/- 2
items
2. Short-term memory fades quickly without rehearsal;
long-term memories persist
3. Memories from long-term memory can be
stimulated with a cue/hint; retrieval of memories lost
from STM do not benefit from the presence of a cue
13
Working Memory: Modern STM
• Baddeley & Hitch (1974)
• Updated the STM model
• Working Memory: Limited capacity system for
temporary storage and manipulation of information for
complex tasks such as comprehension, learning, and
reasoning
1.
2.
Working memory consists of a number of parts
Working memory helps us manipulate information to
carry out complex tasks, not just store information
Consolidation Theory
• This theory posits that when learning occurs it can be
demonstrated immediately after the learning experience
• However, the memory is in an unconsolidated state (STM
processes) which will decay and be forgotten unless
consolidated into permanent memory
Our Changing Views on Consolidation
Reconsolidation
• This theory posits that when a memory is retrieved,
it returns to the STM state
• If undisturbed it will undergo consolidation again
back into LTM
• However, it may not go undisturbed and is
susceptible to alteration at this time
• Since reactivated memory is in a labile state, it can
be blocked (just as in consolidation)
The Hippocampus
Brain structure plays a key role in allowing us to store new
information
• Damage here can lead to amnesia
Penfield & Milner (1958)
• Patient HM is a famous case study in psychology who had his
hippocampus removed to prevent epileptic seizures
• Afterwards Patient HM had great difficulty forming new long-term
memories
• STM or working memory remained intact
• Suggested that the hippocampus is vital for the formation of new
long-term memories
Henry Molaison
(1926-2008) 
People With Hippocampal Damage
Eichenbaum (2002)
• Patient HM showed massive anterograde amnesia
after the surgery
• Two major types of amnesia include:
• Anterograde amnesia – the loss of the ability to
form new memory after the brain damage
occurred.
• Retrograde amnesia – the loss of memory events
prior to the occurrence of the brain damage.
People With Hippocampal Damage
• Episodic memory: ability to recall single events
• Declarative memory: ability to put a memory into words
Patient HM had difficulty with declarative and episodic memory
• Procedural memory: ability to develop motor skills (remembering or
learning how to do things)
Patient HM’s procedural memory remained intact
• Explicit memory – deliberate recall of information that one
recognizes as a memory
• Implicit memory – the influence of recent experience on behavior
without realizing one is using memory
Patient HM also displayed greater “implicit” than “explicit”
memory
The Hippocampus & Declarative Memory
Zola et al. (2000)
• Delayed response task is a test of working memory which
requires responding to a stimulus that one heard or saw a short
while earlier
• Increased activity in the prefrontal cortex during the delay indicates
storing of the memory
• The stronger the activation, the better the performance
The Hippocampus & Declarative Memory
Zola et al. (2000)
Procedure
• Delayed matching-to-sample tasks – a subject sees an
object and must later choose the object that matches
• Delayed non-matching-to-sample tasks– subject sees an
object and must later choose the object that is different than the
sample
Results
• Hippocampal damage impairs performance on both tasks
The Hippocampus & Spatial Memory
Olton & Samuelson (1976)
Procedure
• The Radial Maze
• 8 arms
• All baited
• Rat visits arms until all food is found
• Number of visits is behavioral measure
• 8 is minimum
• Pattern of visits is also recorded
The Hippocampus & Spatial Memory
The Radial Maze
• Task requires procedural memory
• Rat must learn rules of the game: layout of maze,
return trips to visited arms should be avoided, and so
on
• Task also requires working memory
• Rat must remember where it has been in order not to
repeat a visit
• At end of trial, rat can erase working memory and
retain procedural memory
Olton & Samuelson (1976)
The Hippocampus & Spatial Memory
Olton & Samuelson (1976)
• Results
• Rats do very well in this task, achieving an
accuracy level of 7.6 different maze arms among
the first 8 choices after only 15 trials
After 7 days of training 
Olton & Samuelson (1976)
Alternative Explanations
1. Rats just enter arms in sequence thus assuring
themselves of getting food and easing WM requirements
 No - rats do not visit same arms in same order every day pattern of arm visits is nearly random
2. Perhaps rats can smell food at end of arms or smell
scents in visited arms
 No - these possibilities have also been eliminated as
dousing maze with after-shave lotion does not impair
performance
 Also, if after rat has made several choices, arms that it
has chosen are again baited with food, then rat does not
return to those arms
The Hippocampus & Spatial Memory
Olton & Papas (1979)
• Rats with damage to the hippocampus gradually
learn not to enter the never-correct arms
• However, after much training they keep entering
correct arms
Goodrich-Hunsaker & Hopkins (2010)
• Human participants with damage to the
hippocampus are slow to learn which arms are
never correct
• After much training they keep entering correct
arms
The Hippocampus & Contextual Memory
Being tested in the same context helps memory
Godden & Baddeley (1975)
Grant et. al (1998)
The Hippocampus & Contextual Memory
Winocur, Moscovitch, & Sekeres (2007)
Procedure
• Rats test in both familiar and non-familiar areas
Results
• Rats with no damage are helped by familiar place
• Rats with hippocampal damage are not
Interpretation
• Apparently, the brain damaged rats do not depend
on context because they do not remember it
Other research findings concerning
the hippocampus…
• Research in differences in hippocampus size has
revealed conflicting results
• Some evidence suggests that a smaller
hippocampus is associated with better memory
performance
• Hypothesis is that apoptosis improves
hippocampus functioning
• Generally, hippocampus activity is more associated
with memory performance than is the size
Credits
Some slides prepared with the help of the following websites:
• http://web.campbell.edu/faculty/asbury/ppt/chapter13.ppt