Hippocampus

Question 1

Define declarative memory.

Answer 1

Consists of information that is explicitly stored and involves conscious effort to be retrieved.

Question 2

Name the two categories of declarative memory.

Answer 2

Semantic.
Episodic.

Question 3

Define semantic memory.

Answer 3

Facts, meanings, concepts and knowledge about the external world.

Question 4

Define episodic memory.

Answer 4

Personal episodes in time and space.

Question 5

Name and describe the four different types of episodic memory.

Answer 5

Specific events = recalling particular moments from an individual’s autobiographical history.
General events = recalling the feelings associated with a certain type of experience.
Personal facts = information intricately tied to a person’s experiences.
Flashbulb memories = exceptionally vivid and highly detailed snapshots of experiences.

Question 6

Define nondeclarative memory.

Answer 6

Unconscious learning capacities that are expressed through performance rather than conscious retrieval.

Question 7

Name the four categories of nondeclarative memory.

Answer 7

Skills and habits.
Priming.
Basic associative learning.
Non-associative learning.

Question 8

Which brain regions is skills and habits linked with?

Answer 8

Striatum.
Motor cortex.
Cerebellum.

Question 9

Which brain region is priming linked with?

Answer 9

Neocortex.

Question 10

Non-associative learning utilises what?

Answer 10

Reflex pathways.

Question 11

Name the two categories of basic associative learning and which brain regions they’re linked with.

Answer 11

Emotional responses = amygdala via hippocampus.
Skeletal musculature = cerebellum via hippocampus.

Question 12

The density and thickness of the prefrontal cortex’s grey matter is positively correlated with what?

Answer 12

General intelligence.

Question 13

The PFC has reciprocal anatomical connections with where?

Answer 13

Mediodorsal thalamic nucleus.

Question 14

The PFC has direct projections to which four areas?

Answer 14

Brainstem nuclei.
Basal forebrain.
Locus coeruleus.
Raphe nuclei.

Question 15

List the four stages of declarative memory.

Answer 15

Encoding.
Storage.
Consolidation.
Retrieval.

Question 16

Outline the model of prefrontal working memory.

Answer 16

Contains input, temporary storage output and reset signal modules, which are regulated by the activity of neuronal networks.

Question 17

PFC-driven working memory is composed of the visuospatial sketchpad, phonological loop and episodic memory buffer. Describe these concepts.

Answer 17

Visuospatial sketchpad = maintains and manipulates visuospatial images.
Phonological loop = speech perception and storage of speech-based information.
Episodic memory buffer = holds limited information that is integrated from multiple systems.

Question 18

List the four cortical regions of the hippocampus.

Answer 18

Dentate gyrus.
Hippocampus proper (CA1, CA2, CA3).
Subicular complex (subiculum, parasubiculum, presubiculum).
Entorhinal cortex.

Question 19

What is the trilaminar loop?

Answer 19

CA1, CA2, CA3.
The processing centre of long-term memory.

Question 20

Output from the hippocampus passes directly from the subiculum to the what?

Answer 20

Entorhinal cortex and amygdala.

Question 21

Output from the hippocampus passes through the fornix to where?

Answer 21

Anterior nucleus of the thalamus.
Mamillary bodies of the hypothalamus.

Question 22

What is the primary mediator of information coming into and out of the hippocampus to and from the cortex?

Answer 22

Entorhinal cortex.

Question 23

Mossy fibre projections link the dentate gyrus with what?

Answer 23

Pyramidal neurons of the CA3.

Question 24

Outline the information flow through the medial temporal lobe.

Answer 24

Sensory information -> cortical association areas -> parahippocampal and rhinal cortical areas -> hippocampus -> fornix -> thalamus and hypothalamus.

Question 25

What is the importance of spatial memory?

Answer 25

It allows us to form representations of space from landmarks that aid in goal-directed behaviour. It allows us to orient ourselves and our movements in relation to our surroundings.

Question 26

What are place cells?

Answer 26

Hippocampal cells that only fire when you are in a specific location.

Question 27

What is the place field?

Answer 27

The geographical location at which place cells fire.

Question 28

What are grid cells?

Answer 28

Cells in the entorhinal cortex that fire in multiple positions, creating a hexagonal firing pattern that covers an area.

Question 29

Name the five main brain regions associated with spatial memory.

Answer 29

Hippocampus. Prefrontal cortex. Entorhinal cortex. Parietal cortex. Retrosplenial cortex.

Question 30

What is procedural memory?

Answer 30

Motor skill learning.

Question 31

Why is procedural memory considered a type of non-declarative memory?

Answer 31

Conscious retrieval is not necessary for performance of the learned motor skill.

Question 32

What is associative learning?

Answer 32

Two unrelated elements get connected in our brains through the process of conditioning.

Question 33

What is classical conditioning?

Answer 33

A neutral stimulus becomes paired with a stimulus that causes a behaviour. After a while, the neutral stimulus can produce the behaviour by itself.

Question 34

What is operant conditioning?

Answer 34

When a behaviour becomes associated with its consequences, e.g. behaviours with pleasurable consequences are more likely to be repeated.

Question 35

What is non-associative learning?

Answer 35

Behaviour towards a stimulus changes over time in the absence of any conditioning.

Question 36

What is habituation?

Answer 36

A decrease in response to a frequently repeated stimulus.

Question 37

Name two types of non-associative learning methods.

Answer 37

Habituation. Sensitization.

Question 38

What is sensitisation?

Answer 38

An increased reaction to a stimulus after repeated exposure.

Question 39

Define synaptic plasticity.

Answer 39

The activity-dependent modification of the strength or efficacy of synaptic transmission at pre-existing synapses.

Question 40

What is short-term synaptic plasticity?

Answer 40

Changes in synaptic strength that occur on a sub-second timescale and then revert back to 'normal' soon after.

Question 41

What is long-term synaptic plasticity?

Answer 41

Changes in synaptic strength that last from minutes to years.

Question 42

What is the dominant model for how the brain stores information?

Answer 42

Long-term synaptic plasticity.

Question 43

What is the function of back spiking?

Answer 43

In order for information to be available locally at each of the synapses on a postsynaptic cell, information about the firing rate from the presynaptic cell must be propagated backwards from the cell body to each of the synapses.

Question 44

What happens when a pattern of input activity evokes a postsynaptic response greater than the modification threshold?

Answer 44

The active synapses potentiate.

Question 45

What happens when a pattern of input activity evokes a postsynaptic response smaller than the modification threshold?

Answer 45

The active synapses depress.

Question 46

What is the BCM theory?

Answer 46

Homeostatic mechanisms exist to ensure that cortical network activity stays within a useful dynamic range.

Question 47

Most synapses that undergo LTD use what as their NT?

Answer 47

L-glutamate.

Question 48

What is the typical protocol for eliciting LTD?

Answer 48

Prolonged repetitive low frequency stimulation.

Question 49

What determines whether calcium entry through the NMDAR results in LTP or LTD?

Answer 49

The level of NMDAR activation.

Question 50

Describe phosphorylation as a long-term memory consolidation mechanism.

Answer 50

Phosphate groups are added to postsynaptic AMPARs and proteins regulating AMPAR number to increase synaptic effectiveness and form a memory.

Question 51

Why is phosphorylation as a long-term memory consolidation mechanism problematic?

Answer 51

Phosphorylation of a protein is not permanent. Most proteins in the brain have a lifespan of under 2 weeks and undergo a continual process of replacement.

Question 52

What is PKMZ?

Answer 52

An atypical isoform of protein kinase C (PKC).

Question 53

What are the two main roles of PKMZ in memory formation?

Answer 53

Maintains the cellular changes that occur during memory formation. May restabilise an updated memory.

Question 54

Local protein synthesis in dendrites is required for what?

Answer 54

The rapid enhancement of synaptic transmission induced by exposure to the growth factor BDNF.

Question 55

What are the effects of the activation of mGluRs on synaptic plasticity and memory formation?

Answer 55

Stimulates dendritic translation. Produces a form of LTD that requires dendritic translation. Produces a protein-synthesis-dependent lengthening of spines.