Psychology Notes Neuropsychology of Memory Notes
These notes aim to provide an understanding of cognitive neuropsychological models of high level behaviour such as remembering, recognising, short and long term memory and the role of the brain in this behaviour.
These notes are informative, precise, easy to follow and are drawn from a wide range of sources utilising additional course reading and independent reading. ...
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Visual Memory Deficit Amnesia
Greenberg & Rubin (2003) – burger example
Smell of burgers leads to activation in olfactory cortex
This via MTL mediation would activate a pattern of firing in visual cortex that represents the memory of a friend once cooking them
This activity in visual cortex – may stimulate new activity in audiotry cortex - represents the sound of a conversation once had with that friend
This is the CASCADE of activation
This activity would also stimulate regions dedicated to language, narrative + emotion - impart the emotional tone to the memory
The recall of an autobiographical memory occurs over one measurable time period - but not in one brain location => it is located in time – but distributed in space.
Rubin & Greenwood (1998) When an autobiographical memory is recalled info in widely separated areas of cortex are excited :
E.g. a familiar sound may lead to activation in auditory cortex – which either directly or via the hippocampal mediation might activate a pattern of firing in visual cortex – stimulating a visual image
This activity in visual cortex may in turn stimulate new activity in visual, auditory + other cortices - stimulating visual images, sounds, smells - while feed-backing to the original pattern of firing in auditory cortex cascade of activation – produces a patterns of firing similar to that present during the original experience
Most memories have strong visual component:
Crawley & Eacott (2006)
Asked to recollect + describe a memory from childhood investigated the extent to which the memory had visual, auditory, spatial etc aspects
Visual detail is the largest + most regularly reported detail - this is higher than any other sensory component
Suggestive that memories rely heavily on visual representations
Rubin (2006)
Participants are given a cue word - asked to retrieve and episodic memory associated with that word whislt undergoing fMRI
Asked to hit a button once memory brought to mind
Large activation of the hippocampus at memory retrieval, PFC activated when making a decision on the memory to think of
Visual cortex was v. active - retrieval of the memory activated the visual cortex
Further suggests there is a large amount of visual info in memory representations
What happens to EM if visual association cortex is damaged?
New experiences will have a degraded visual component and so anterograde memories will be formed with this degraded input. Relative absence of visual component will affect but may not be devastating to memory integrity.
Pre-existing memories (i.e. retrograde) were formed of events that included an intact visual component. Stored visual component will be degraded/lost.
For retrograde memories the lack of visual component may also prevent the cascade of associations to other modality components, affecting retrieval of them too. This will effect all retrograde memories equally, so there will be no temporal gradient to retrograde amnesia.
Hypothesis: the loss of visual association cortex will result in a form of amnesia with the above characteristics. Called Visual Memory Deficit Amnesia (VMDA)
Differences between MTL amnesia
Differences between VMDA + cortical/retinal blindness
New exp will not have a visual component + so AA will be formed without it
Visual association cortex still exists - but will receive no visual input
Input from other modalities may call up associated visual images from memory to be incorporated
Retrograde memories (formed before blindness) were formed of events that included a visual component
Visual association cortex still exists (although receives no new input)
Visual memories stored in visual association cortex will still be available
The visual memories stored in visual association cortex can still cascade to associations to othermodality components - should be no effect of retrograde memories
Detecting a patient with VMDA – Farah’s Model
Patient must be able to detect, draw or describe the visual properties of an object
Demonstrates that the deficit could not have arisen from motor, perceptual or linguistic impairment
Patient must not be able to recognise an object on sight alone - indicating its name or function cannot match an intact percept of an object to a stored LTM representation of the object
The patient should not be able to draw an object from memory, describe its visual characteristics from memory , or detect its visual image upon introspection cannot access the stored LTM representation of the object
Temporal Gradient – Rubin & Greenwood (1998)
Predicted that these amnesic patients would have no sparing of childhood memories - which characterises nearly all other forms of amnesia
The temporal gradient in more common forms of amnesia is thought to arise because consolidation is achieved at various stages of completion leading to a failure in retention of the most recent memories
In this predicted form of amnesia - the deficit arises NOT from a loss of retention of incompletely consolidated material - but from a loss of visual info itself - even older consolidated memories would be left with big gaps
Rubin & Greenberg (1998)
11 cases in the literature met the criteria for a visual memory deficit
The data available fitted the predictions of VMDA with only 4 exceptions
VMDA is a new classification of amnesia - unlike other forms of amnesia – is caused by a loss of posterior neocortex rather than damage to the MTL or diencephalon region
Although it is rare – it is frequent enough to establish that it properties distinguish it from other types of amnesia
Case MH – supportive of VMDA Ogden (1993)
24yr old man injured in motorcycle crash
Damage bilaterally to occipital lobes - no damage reported to frontal or temporal lobes (not MTL or diencephalon – not standard amnesia)
Originally assessed as blind - 21m later reassessed + responded to some visual stimuli
He could copy line...
Buy the full version of these notes or essay plans and more in our Neuropsychology of Memory Notes.
These notes aim to provide an understanding of cognitive neuropsychological models of high level behaviour such as remembering, recognising, short and long term memory and the role of the brain in this behaviour.
These notes are informative, precise, easy to follow and are drawn from a wide range of sources utilising additional course reading and independent reading. ...
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