Ultra Review Chapter 12

behavior can be broken down into
learned behavior

Associative learning
occurs when an organism
forms a connection between two features of its environment.

Classical conditioning
which allows organisms to learn about signals that predict important events, falls into
this category.

Non – Associative learning
including the processes of habituation and sensitization, involves changes in the magnitude of responses to stimuli rather than the formation of connections between specific elements or events.

Aplysia californica
invertebrate sea slug frequently
used as a subject of experiments
on learning and memory.

Short term habituation
decreasing neurotransmitter

long term habituation
changes to the NMDA glutamate receptors

post synaptic changes in sensitization
more AMPA glutamate

presynaptic changes
Longer action potentials produce a greater influx of calcium into the sensory
neuron, which in turn results in the release of larger amounts of neurotransmitter
by the sensory axon terminal. The increased release of neurotransmitter produces a
stronger response by the motor neurons and the gill muscles, leading to the stronger
gill-withdrawal reflex that we observe in sensitization.

retrograde signal
It also appears that the coordination of pre- and postsynaptic changes occurs through retrograde signals from the postsynaptic motor cell back to the presynaptic sensory cell or interneuron

The Atkinson-Shiffrin Model
of Memory
-information is processed in a sequence of steps

Declarative and procedural
memories differ in one other important way.
Declarative memories are typically recalled consciously or explicitly, whereas procedural memories are usually recalled
unconsciously or implicitly. Learning a skill, such as driving a car, requires quite a bit of attention and conscious effort.

Once mastered, however, a skill such as driving
can become quite automatic. In addition to procedural memories, classical conditioning, habituation, and sensitization are also considered examples of nondeclarative or implicit processes.

As we observed previously, however, trace conditioning (a type of classical conditioning) shares many similarities with declarative memory.

The distinction between explicit and implicit memories can be demonstrated in
patients suffering from a type of memory loss known as anterograde amnesia.
In cases of anterograde amnesia, patients have good recall for events that occurred prior to the time of their brain damage, but they seem unable to remember anything they
experience following their brain damage.

However, the inability of these patients to remember the present, such as the name of the current president of the United States, is not due to a complete memory failure.

Squire (1987) demonstrated that patients with anterograde amnesia were able to learn to solve the Tower of Hanoi puzzle, in which a stack of rings must be moved from one peg to another one at a time without placing a larger ring on top of a smaller ring

Karl Lashley
failed with engram

Wilder Penfield
Penfield reported[8] that stimulation of the temporal lobes could lead to vivid recall of memories

-bought attention to the idea of a possible role for the temporal lobe in the formation and retention of
long-term memories.

Surgical Removal of Temporal
Lobe Tissue in Patient H. M.
To control life-threatening seizures,
patient H. M. underwent surgery that
removed the hippocampus, amygdala,
and part of the association cortex from
both temporal lobes.

The good news for H. M.
was that his seizure disorder was much improved and
his personality, vocabulary, and above-average IQ appeared unchanged

bad news
He remembered most of the information he had acquired prior to surgery, but his anterograde amnesia was profound.

He seemed completely unable to transfer any new information
about people, places, events, and numbers from short-term memory to long-term memory.

however H.M’s surgery did not effect all types of memory equally
however H.M’s surgery did not effect all types of memory equally

H.M proves that
provides further support for the differentiation of explicit
and implicit memories as well as for the stage approach to memory articulated by
the Atkinson-Shiffrin model.

amage to the temporal lobe like H.M got
Damage to the medial temporal lobes, such as in the
case of H. M., affects explicit but not implicit memories

H. M.’s damage does not affect long-term memories that have already been stored, but it does affect the transfer
of new information from short-term to long-term memory

since the long term memory that was there before the surgery remained, its unlikely that the all long term memory is stored in teh hippocampus

The fact that patients such as H. M. still retain fairly stable memories dating from their presurgical lives suggests that the actual representations of these memories do not reside in the medial temporal lobe itself.

Nor is the medial temporal lobe necessarily essential for the
retrieval of stored memories.

Anterograde Amnesia
loss of memories for events that happened after brain damage

inability to retain new material for more than a brief period

Retrograde Amnesia
loss of memory for events that occurred shortly before brain damage
not rare after damage

delayed nonmatching to sample
(DNMS) task
A standard test
of memory in which the subject
must identify the novel member of
a stimulus pair following a delay.

rhesus monkeys
were given temporal lobe lesions

-found that monkeys with medial temporal lobe lesions in both hemispheres performed poorly on the DNMS task, especially as the delay period increased. Experienced control monkeys could select the correct stimulus about 90 percent of the time.

The amygdala
appears to play a role in processing emotional memories, but damage to the amygdala alone does not produce anterograde amnesia.

part 1of the pathway
From cortex via the perforant pathway and synapsing on the dentate gyrus

part 2 of the pathway
From dentate gyrus via the mossy fibers and synapsing on the CA3

part 3 of the pathway
From CA3 via the schaffer collaterals and synapsing with cells of CA1

The Diencephalon and Memory
The hippocampus and other areas of the temporal lobe are tightly connected to the thalamus. Disruption to these structures or to their connections appears to result in

Case studies of patients with diencephalic lesions support the
role of this area in memory.

Patient N. A.
uffered brain damage as a result of a freak accident in which he was stabbed through the nostril with a fencing foil (a long thin metal blade) held by one of his roommates.

N. A. suffered a lesion in his left dorsomedial thalamus

Patient N. A. experienced significant anterograde amnesia as
well as some retrograde amnesia, affecting memories from several years prior to his accident

Similraties between N.A and H.M
Both show normal short term memory but are impaired in forming declarative (but not procedural) long term memories

Are these similarities because the medial temporal damage in HM and the midline diencephalic region damage in NA are part of a larger memory system??

mamillary bodies
lost by N.A, implicated in long term explicit memory

Korsakoff’s syndrome
Chronic alcoholics who develop Korsakoff’s syndrome experience
anterograde amnesia similar to that of patients H. M. and N. A.

Alcoholism often results in a deficiency of thiamine, also known as vitamin B1. Thiamine is important to nervous system functioning because it participates in the synthesis of the neurotransmitter acetylcholine.

Untreated thiamine deficiencies lead to damage in the dorsomedial thalamus and mammillary bodies of the diencephalon

more on Korsakoff
In addition to their anterograde amnesia, patients with Korsakoff’s syndrome usually experience severe retrograde
amnesia, possibly due to lesions in the cerebellum, brainstem, and cortex as well as in the diencephalon. Animal research confirms observations made in these human case

Monkeys with lesions of the anterior and dorsomedial nuclei of the thalamus and of the mammillary bodies have great difficulty with the DNMS task

Semantic memory and the cortex
There appears to be considerable evidence that semantic knowledge, or our basic knowledge of facts and language, is widely distributed in the cortex.

Different areas of association cortex are activated during semantic memory tasks based on the particular characteristics of the concept being processed.

The distribution of semantic knowledge is also supported by case studies of patients with damage to their association cortex
describe a patient who had substantial difficulty describing living things but who retained a perfect capacity for describing inanimate objects such as wheelbarrows.

who experience damage to the prefrontal areas of the cortex often experience a memory
deficit known as source amnesia.
independent episodic memory store for our personal
experiences is supported by case studies with patients with cortical damage

source amnesia.
These patients retain their semantic memories
but are unable to remember how and when they learned a bit of information.

anterior prefrontal cortex and the posterior cingulate cortex
participate in the retrieval of personal, episodic memories

viewed brain activity while participants listened to their own autobiographical stories
or to autobiographical stories written by other people. When listening to their own
autobiographical material, participants showed greater activation in the right frontal
and temporal lobes than they did when they listened to the stories of other people’s

However, other areas appear to
be differentially active. When considering reality,
structures associated with episodic
memory, such as the prefrontal cortex and posterior cingulate cortex, were active.
These results imply that we consult our personal experience to determine reality.

areas associated with semantic processing,
such as the left inferior frontal gyrus (IFG) showed greater activity (ibid.). Recall that
the IFG showed greater activation when semantic rules of language and world knowledge
were violated (Hagoort et al., 2004), which of course they are when imagining a
conversation with Cinderella. Disturbances in this distinction might form the basis
for the delusions, or false beliefs, that characterize some psychological disorders

central executive
The dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate cortex (ACC)

Evidence for an executive role for the anterior cingulate cortex (ACC) in shortterm
memory comes from comparisons of people with large or small short-term
memory capacities for verbal informatio
People with large capacities show more
activation of the ACC than people with smaller capacities

These observations support a role for the ACC
in the
processing of verbal information in short-term memory.

The striatum
ncluding the basal ganglia
and nucleus accumbens, are involved with the formation of procedural memories

the basal ganglia
are part of our motor system
o it would seem logical that these structures would be
involved in the learning and memory of motor patterns. The nucleus accumbens contributes
an evaluation of emotion and reward to the learning of procedures

The role of the striatum in procedural
but not declarative,
memories was demonstrated by observing the effects of lesions on
rats trained in one of two different maze tasks

Different brain lesions affect performance in the two types of mazes.
Lesions to structures associated with the hippocampus impaired performance on
the declarative task (the standard maze), but performance on the procedural task
(the light maze) remained normal. However, rats with lesions in the basal ganglia
performed poorly on the procedural task but experienced little difficulty with the
declarative task.

tasks are more complicated
such as asking the mouse to choose between two escape
boxes with equal levels of illumination, performance is no longer linear. Instead,
performance increases as stress increases to a certain point and then decreases with stronger stress

hippocampus and stress
LTP in the hippocampus is actually
enhanced by emotions The key to this
discrepancy is timing. the onset of stress initially
enhances memory formation, as in the case of traumatic and flashbulb memories.
This initial phase of seconds or minutes, however, is followed by a refractory period
of hours or even days, during which the ability to form new memories is impaired

3 major types of memory: 1. working 2.Short term 3. long term Working memory very brief (few seconds to minutes) retention of sensory input kept while something is being evaluated and acted upon can be moved to short term memory …

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