Memory 2 - Consolidation

Question 1

What are the 3 stages of visual memory?

Answer 1

• Iconic
• Short term
• Long term

Question 2

What is iconic memory?

Answer 2

An immediate, but very short lasting retention of visual information, lasting no longer than one second.

Question 3

What is visual short term memory?

Answer 3

A more long lasting form which keeps images active for processing within the visual cortical neurons.

Question 4

What is visual long term memory?

Answer 4

Allows us to remember and recognise visual stimuli for as long as an entire lifetime.

Question 5

What is the mechanism behind iconic memory?

Answer 5

Mechanisms in the eye, e.g. the retina. The brightness of the stimuli seems to leave an imprint on the retinal systems, causing the image to remain much like the after-effect of a camera flash causes.

Question 6

What is the mechanism behind visual short term memory?

Answer 6

Sustained neural activity in the inferior temporal cortex which causes the image to remain for several seconds.

Question 7

What is the mechanism behind visual long term memory?

Answer 7

No concrete findings as yet. Patients with sever temporal lobe damage suffer from amnesia, characterised by impairments in visual recognition memory..

Question 8

What is repetition suppression?

Answer 8

The reduced cortical/neuronal response when an object is recognised from long term memory. (Fahy et al., 1993; Meister et al., 2005; van Turennout et al., 2000).

Question 9

Which type of memory did Sperling’s array test?

Answer 9

Iconic memory

Question 10

What was found from Sperling’s array experiment and how can this be explained?

Answer 10

• That participants could remember a greater percentage of the letters (75%) in partial report conditions, but only 35-40% in the full report condition.
• That, if participants are asked at a 1 second delay, the advantages of the partial report are lost, with accuracy dropping back down to 35-40%.

This can be explained by the 1 second duration of iconic memory. In the full report conditions, only 4/5 letters can be reported before the visual memory/representation of the image decays. In the partial reports, pps could report a large percentage of the line, as there were less letters, before their memory for it decayed.
However, when the questions were delayed by a second, the representation had decayed before they could report more than 40%.

Question 11

What does perceptual learning relate to?

Answer 11

Learning of perceptual information, such as visual stimuli.

Question 12

What does procedural memory relate to?

Answer 12

Memory for skills and/or processes. E.g. riding a bike, making a tea, etc.

Question 13

What is the mnemonic function of a neuron?

Answer 13

Memory processing ability of a neuron

Question 14

True or false: there is a clear distinction between perception and memory.

Answer 14

False: there is no clear distinction yet, between perception and memory, reinforcing the notion that memory is a fundamental process that underlies other functions in the brain.

Question 15

What is associative learning?

Answer 15

Learning that involves the formation of links between stimulus and response. (Pavlovian conditioning)

Question 16

What is instrumental learning?

Answer 16

Learning to produce behaviours to bring about a desired effect/event. e.g. the rat pressing the lever for food.

Question 17

What is the function of consolidation?

Answer 17

To enable a memory to be stabilised into a long term form.

Question 18

How can the lack of spatial resolution in patient studies be made up for?

(e.g. how can we get around the fact that multiple brain areas are often damaged/removed, meaning we cannot always reliably attribute impairments to one or two brain areas alone?)

Answer 18

We can ensure we test a very large sample and then correlate the extent of damage to a specific target area with the impairments that we observe.

Question 19

What is Urbach-Wiethe disease?

Answer 19

A degenerative disease which results in neuronal cell death in both sides of the amygdala.

Question 20

Why does Urbach-Wiethe disease occur?

Answer 20

Genetic disorder which causes the build up of calcium deposits in the amygdalae, leading to neuronal cell death in affected areas.

Question 21

Are there any diseases which specifically target and damage only the amygdala? If so, what are they called?

Answer 21

Urbach-Wiethe disease.

Question 22

What is aspiration?

Answer 22

A method of causing damage to a specific area of the brain, which involves sucking out parts of the brain.

Question 23

What are electrolytic lesions?

Answer 23

Lesions to the brain caused by induced electrical currents.

Question 24

What are excitotoxic lesions?

Answer 24

Lesions caused by chemicals which over-stimulate neurons to death.

Question 25

What did Gale et al (2004), Marren (1999), Nader et al., (2001), and Sananes and Davis, (1992) find about lesions to the amygdala in rats?

Answer 25

Lesions to the amygdala impair rats' pavlovian fear conditioning, regardless of whether the lesions occur before, during or after learning.

Question 26

What did Antoniadis et al., (2007) find about lesions to the amygdala of monkeys?

Answer 26

That impairments in Pavlovian fear conditioning were induced, but only if the lesions were made before learning.

Question 27

How can specific brain areas be silenced - how can their activity be decreased or inhibited?

Answer 27

Using chemicals: - Tetrodotoxin (TTX): which blocks sodium channels, preventing action potentials from firing in the designated brain area. - Baclofen and Muscimol, which are agonists for GABA receptors. As GABA receptors inhibit neurons, increasing their activation leads to a functional silencing within target areas.

Question 28

What did Muller et al., (1997) find about the amygdala in rats?

Answer 28

That fear memories were significantly impaired when the amygdala was functionally silenced before fear conditioning and before fear testing.

Question 29

What is cellular consolidation?

Answer 29

The stabilisation of a memory which requires a multitude of cellular processes.

Question 30

What is the evidence that supports the idea that memory consolidation requires the synthesis of new proteins?

Answer 30

There is increased gene expression at learning - suggesting that the proteins being produced as a result of this gene expression are required for consolidation.

Question 31

What does arc stand for and why is it needed?

Answer 31

Activity-related cytoskeletal-associated protein is supposedly required for memory consolidation.

Question 32

What did Ploski et al., (2008) find about the need for arc protein?

Answer 32

Found that the consolidation of fear memories was impaired when the synthesis of arc protein in the amygdala was inhibited.

Question 33

What did Ploski et al., (2008) find about the regulators of arc expression?

Answer 33

The increase in arc expression was dependent on the increase of signalling in the ERK/MAPK pathway.

Question 34

What regulates arc expression and why?

Answer 34

The ERK/MAPK pathway involves protein enzymes which phosphorylate enzymes, activating them, subsequently leading to the activation of further downstream components of the pathway.

Question 35

What did Shafe et al (2000) find out about the importance of ERK/MAPK signalling?

Answer 35

The inhibition of the ERK/MAPK pathway impairs the consolidation of fear memories in the amygdala.

Question 36

What did Lee and Kim, (1998) and Miserendino, (1990) find about NMDA receptors and fear conditioning?

Answer 36

The introduction of an NMDA antagonist blocks the acquisition of fear conditioning. Supposedly because the NMDA receptors could not be activated, so the ERK/MAPK pathway was not activated and therefore the arc protein was not expressed/not enough was produced.

Question 37

What is the NMDA receptor antagonist which is used in a study by Lee and Kim, (1998) and Miserendino, (1990) ?

Answer 37

AP-5

Question 38

What did Bauer et al (2002) find about NMDA receptor antagonism?

Answer 38

That NMDA receptor antagonism causes impairments in STM as well as LTM, suggesting that NMDA receptors may be involved in the general process of learning/memory acquisition.