Hippocampus and Memory

Question 1

What is the result of a hippocampal lesion?

Answer 1

Anterograde episodic amnesia

Question 2

What are the 2 main types of long-term memory?

Answer 2

Declarative

Non-declarative

Question 3

What are the 2 types of declarative memory?

Answer 3

Episodic

Semantic

Question 4

What are the 4 types of non-declarative memory?

Answer 4

Procedural
Priming
Classical conditioning
Non-associative learning

Question 5

What is the Standard Consolidation model of declarative memory?

Answer 5

Fast-changing connections between medial temporal lobe (MTL) and 2 cortical areas - change when remembering info
Slow-changing connections between 2 cortical areas - change when memory becomes embedded
MTL binds together cortical memory traces - by repeated reactivation - become independent of MTL

Question 6

What is the evidence against the SC model of declarative memory?

Answer 6

Individuals with developmental hippocampal damage
Impaired episodic memory
Normal semantic knowledge
Dissociation between semantic and episodic memory

Question 7

Is the hippocampus required for semantic recall?

Answer 7

No

Question 8

Is the hippocampus required for episodic recall?

Answer 8

Yes

Question 9

What is the evidence against a permanent role of the MTL in declarative memory?

Answer 9

Graded retrograde amnesia in MTL lesion patients

Gradient from loss of recent memory - preservation of remote memory

Question 10

What is the Multiple Trace theory of declarative memory?

Answer 10

Episodic memories stored in hippocampus
Every time event remembered - make new memory trace in hippocampus - overlaps old traces
Re-encoding memory multiple times causes them to be semanticised - integrates with semantic memory stores
Episodic component of memory (spatial and temporal context) requires hippocampus
Semantic component (basic event outline) does not

Question 11

Define encoding

Answer 11

Linking neurons into networks that can store memories

Question 12

Define consolidation

Answer 12

Strengthening memory traces

Question 13

What are Martin et al.’s (2000) 4 proposed tests for the synaptic plasticity and memory hypothesis?

Answer 13

Detectability - of LTP after learning
Anterograde alteration - if LTP disruption blocks learning
Retrograde alteration - if disruption of established LTP disrupts previously-acquired memories
Mimicry - artificially induce memory using LTP

Question 14

What is traditionally thought to be the role of PKMzeta?

Answer 14

LTP maintenance

Question 15

What does ZIP do?

Answer 15

Prevents PKMzeta auto-catalysis

Question 16

What is the currant bun model of memory storage?

Answer 16

Memory trace involves potentiation in some CA1 cells - but not others

Question 17

What are the 2 types of oscillations involved in memory in the hippocampus?

Answer 17

Theta

Sharp wave ripples

Question 18

When do theta oscillations occur in the hippocampus and what is their role?

Answer 18

During active experience

Online learning - encoding

Question 19

When do sharp wave ripples occur in the hippocampus and what is their role?

Answer 19

During offline post-learning phases

Post-experience consolidation - e.g. slow wave sleep

Question 20

What is the effect of shutting down the hippocampus during sharp wave ripples in sleep?

Answer 20

Impairs learning - no memory consolidation

Question 21

What is a possible neural mechanism for system consolidation?

Answer 21

Reactivation

Question 22

What is likely to be the purpose of sequential place cell reactivation during slow wave sleep?

Answer 22

Strengthen connections between neurons that fired together

Enable episodic memory - link objects/events to places

Question 23

Define pattern completion

Answer 23

Process where system can recover entire familiar stimulus - when presented with only part of it

Question 24

Which process is performed by auto-associative networks for memory retrieval?

Answer 24

Pattern completion

Question 25

What are the 2 components of auto-associative networks that enables them to perform pattern completion?

Answer 25

Dense recurrent collateral projections

Recurrent synapses strengthened by Hebbian plasticity - simultaneous pre- and post-synaptic spike

Question 26

Which area of the hippocampus may be an auto-associative network?

Answer 26

CA3