3-09 Learning, Memory, Amnesia And Brain Function (Part 2)

Front 1

Objective

Distinguish between retrograde and anterograde amnesia.

Back 1

Anterograde amnesia is characterized by a loss of memories for events that happened after the brain damage. Retrograde amnesia is characterized by loss of memory for events that occurred before the brain damage.

Front 2

Objective

Indicate which aspects of H.M.'s memory are impaired and which are intact.

Back 2

In summary, H.M. has:
1. Normal, short-term memory or working memory.
2. Severe anterograde amnesia for declarative memory—that is, difficulty forming new declarative memories.
3. Intact procedural memory.
4. Better implicit than explicit memory.

Front 3

Objective

Discuss the relationship between memory performance and: (1) hippocampus size, (2) neural activity in the hippocampus.

Back 3

1. Studies of children, adolescents, and young adults have found better memory performance, on the average, for those with a smaller hippocampus. One hypothesis is that apoptosis (programmed cell death) may strengthen the hippocampus by weeding out ineffective neurons. As people grow older, the hippocampus gradually shrinks; memory is more likely to be impaired among people whose hippocampus shrinks faster than average.

2. There is an inverse correlation between neural activity in the hippocampus and memory performance. People who show relatively levels of activity in their hippocampus while doing a memory task tend to have low levels of performance on those tasks.

Front 4

Objective

Describe three hypotheses about the role of the hippocampus in memory.

Back 4

1. The hippocampus is critical for declarative memory, especially episodic memory. Hippocampal damage impairs performance on a delayed matching-to-sample task, in which the participant sees an object (the sample) and then, after a delay, gets a choice between two objects, from which s/he must choose the one that matches the sample.

2. The hippocampus is especially important for spatial memories. Electrical recordings indicate that many neurons in a rat’s hippocampus are tuned to particular spatial locations, responding best when an animal is in a particular place or looking in a particular direction. When people perform spatial tasks, such as imagining the best route between one friend’s house and another, fMRI data show enhanced activity in the hippocampus.

3. The hippocampus is necessary for configural learning, in which the meaning of a stimulus depends on what other stimuli are paired with it. For example, an animal might have to learn that stimulus A signals food, B also signals food, but a combination of A and B signals no food. In many cases, hippocampal damage impairs configural learning. However, such damage also impairs memory on non-configural tasks when they are sufficiently difficult. Also, hippocampally damaged animals do eventually learn difficult configural tasks.

Front 5

Objective

Identify the effects of hippocampal damage on rats’ maze performance.

Back 5

Rats with damage to the hippocampus are unable to consolidate memories (convert short- term memories into long-term memories). Thus, rats with damage to this region may be able to learn proper responses in the Morris water maze task, but they forget rapidly, suggesting that they cannot consolidate long-term memories.

Front 6

Objective

Explain how emotional response affects memory consolidation.

Back 6

Stressful or emotionally exciting experiences increase the secretion of epinephrine and cortisol. Small to moderate amounts of cortisol activate the amygdala and hippocampus, where they enhance the storage and consolidation of recent experiences. Prolonged stress, which releases even more cortisol, can impair memory, perhaps by damaging neurons in the hippocampus through overstimulation.

Front 7

amnesia

Back 7

memory loss

Front 8

retrograde amnesia

Back 8

Loss of memory for events that occurred shortly before brain damage

Front 9

anterograde amnesia

Back 9

Loss of memories for events that happened after brain damage

Front 10

episodic memory

Back 10

Memories for single events

Front 11

declarative memory

Back 11

Ability to state a memory in words

Front 12

procedural memory

Back 12

The development of motor skills and responses

Front 13

explicit memory

Back 13

Deliberate recall of information that one recognizes as a memory

Front 14

implicit memory

Back 14

Influence of recent experience on behavior, without necessarily realizing that one is using memory

Front 15

delayed matching-to-sample task

Back 15

Task in which an animal sees an object (the sample) and then, after a delay, gets a choice between two objects, from which it must choose the one that matches the sample

Front 16

delayed nonmatching-to-sample task

Back 16

The procedure is same as in the delayed matching-to-sample task, except the animal must choose the object that is different from the sample

Front 17

radial maze

Back 17

Maze that has eight or more arms, some of which have food or other reinforcer at the end; used in spatial memory experiments

Front 18

Morris water maze task

Back 18

Task in which a rat must swim through murky water to find a rest platform that is just under the surface; spatial memory task

Front 19

configural learning

Back 19

Learning in which the meaning of a stimulus depends on what other stimuli are paired with it

Front 20

consolidation

Back 20

Process by which short-term memories are converted in long-term memories