Memory 2 - Consolidation Flashcards
What are the 3 stages of visual memory?
- Iconic
- Short term
- Long term
What is iconic memory?
An immediate, but very short lasting retention of visual information, lasting no longer than one second.
What is visual short term memory?
A more long lasting form which keeps images active for processing within the visual cortical neurons.
What is visual long term memory?
Allows us to remember and recognise visual stimuli for as long as an entire lifetime.
What is the mechanism behind iconic memory?
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.
What is the mechanism behind visual short term memory?
Sustained neural activity in the inferior temporal cortex which causes the image to remain for several seconds.
What is the mechanism behind visual long term memory?
No concrete findings as yet. Patients with sever temporal lobe damage suffer from amnesia, characterised by impairments in visual recognition memory..
What is repetition suppression?
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).
Which type of memory did Sperling’s array test?
Iconic memory
What was found from Sperling’s array experiment and how can this be explained?
- 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%.
What does perceptual learning relate to?
Learning of perceptual information, such as visual stimuli.
What does procedural memory relate to?
Memory for skills and/or processes. E.g. riding a bike, making a tea, etc.
What is the mnemonic function of a neuron?
Memory processing ability of a neuron
True or false: there is a clear distinction between perception and memory.
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.
What is associative learning?
Learning that involves the formation of links between stimulus and response. (Pavlovian conditioning)
What is instrumental learning?
Learning to produce behaviours to bring about a desired effect/event. e.g. the rat pressing the lever for food.
What is the function of consolidation?
To enable a memory to be stabilised into a long term form.
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?)
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.
What is Urbach-Wiethe disease?
A degenerative disease which results in neuronal cell death in both sides of the amygdala.
Why does Urbach-Wiethe disease occur?
Genetic disorder which causes the build up of calcium deposits in the amygdalae, leading to neuronal cell death in affected areas.
Are there any diseases which specifically target and damage only the amygdala? If so, what are they called?
Urbach-Wiethe disease.
What is aspiration?
A method of causing damage to a specific area of the brain, which involves sucking out parts of the brain.
What are electrolytic lesions?
Lesions to the brain caused by induced electrical currents.
What are excitotoxic lesions?
Lesions caused by chemicals which over-stimulate neurons to death.
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?
Lesions to the amygdala impair rats’ pavlovian fear conditioning, regardless of whether the lesions occur before, during or after learning.
What did Antoniadis et al., (2007) find about lesions to the amygdala of monkeys?
That impairments in Pavlovian fear conditioning were induced, but only if the lesions were made before learning.
How can specific brain areas be silenced - how can their activity be decreased or inhibited?
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.
What did Muller et al., (1997) find about the amygdala in rats?
That fear memories were significantly impaired when the amygdala was functionally silenced before fear conditioning and before fear testing.
What is cellular consolidation?
The stabilisation of a memory which requires a multitude of cellular processes.
What is the evidence that supports the idea that memory consolidation requires the synthesis of new proteins?
There is increased gene expression at learning - suggesting that the proteins being produced as a result of this gene expression are required for consolidation.
What does arc stand for and why is it needed?
Activity-related cytoskeletal-associated protein is supposedly required for memory consolidation.
What did Ploski et al., (2008) find about the need for arc protein?
Found that the consolidation of fear memories was impaired when the synthesis of arc protein in the amygdala was inhibited.
What did Ploski et al., (2008) find about the regulators of arc expression?
The increase in arc expression was dependent on the increase of signalling in the ERK/MAPK pathway.
What regulates arc expression and why?
The ERK/MAPK pathway involves protein enzymes which phosphorylate enzymes, activating them, subsequently leading to the activation of further downstream components of the pathway.
What did Shafe et al (2000) find out about the importance of ERK/MAPK signalling?
The inhibition of the ERK/MAPK pathway impairs the consolidation of fear memories in the amygdala.
What did Lee and Kim, (1998) and Miserendino, (1990) find about NMDA receptors and fear conditioning?
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.
What is the NMDA receptor antagonist which is used in a study by Lee and Kim, (1998) and Miserendino, (1990) ?
AP-5
What did Bauer et al (2002) find about NMDA receptor antagonism?
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.
