forms a connection between two features of its environment.
invertebrate sea slug frequently
used as a subject of experiments
on learning and memory.
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.
memories differ in one other important way.
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.
patients suffering from a type of memory loss known as anterograde amnesia.
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
-bought attention to the idea of a possible role for the temporal lobe in the formation and retention of
Lobe Tissue in Patient H. M.
patient H. M. underwent surgery that
removed the hippocampus, amygdala,
and part of the association cortex from
both temporal lobes.
his personality, vocabulary, and above-average IQ appeared unchanged
He seemed completely unable to transfer any new information
about people, places, events, and numbers from short-term memory to long-term memory.
and implicit memories as well as for the stage approach to memory articulated by
the Atkinson-Shiffrin model.
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.
inability to retain new material for more than a brief period
not rare after damage
of memory in which the subject
must identify the novel member of
a stimulus pair following a delay.
Case studies of patients with diencephalic lesions support the
role of this area in memory.
N. A. suffered a lesion in his left dorsomedial thalamus
well as some retrograde amnesia, affecting memories from several years prior to his accident
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??
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
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
Different areas of association cortex are activated during semantic memory tasks based on the particular characteristics of the concept being processed.
who experience damage to the prefrontal areas of the cortex often experience a memory
deficit known as source amnesia.
experiences is supported by case studies with patients with cortical damage
but are unable to remember how and when they learned a bit of information.
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
be differentially active. When considering reality,
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
memory comes from comparisons of people with large or small short-term
memory capacities for verbal informatio
activation of the ACC than people with smaller capacities
processing of verbal information in short-term memory.
and nucleus accumbens, are involved with the formation of procedural memories
are part of our motor system
involved in the learning and memory of motor patterns. The nucleus accumbens contributes
an evaluation of emotion and reward to the learning of procedures
memories was demonstrated by observing the effects of lesions on
rats trained in one of two different maze tasks
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
tasks are more complicated
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
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