Lecture 16- Memory Flashcards
What aspects of memory suggest it is not a single function?
Episodic – memory of specific events. Semantic – memory for facts. Working – short term, rehearsal. Procedural – motor memory.
How is memory not a single function?
These memory types can be dissociated from each other and disrupted independently.
What is damage to memory referred to as?
Amnesia
What is neurology within memory?
Hippocampus, Amygdala and related structures in the medial temporal lobe
What is anterograde amnesia?
Poor ability to acquire new information but info before and working memory is spared.
What are the specifics of anterograde amnesia?
-Impaired declarative memory eg episodic and semantic -Preservation of non-declarative memory eg perceptual, procedural
What are the 2 causes of anterograde amnesia?
-Disorders
-Temporal lobectomy
What disorders are related to anterograde amnesia?
Korsakoff syndrome -Thiamine deficiency, due to alcoholism and poor diet, impaired absorption of thiamine from intestine.
How is Temporal lobectomy linked to anterograde amnesia?
-Patients with intractable seizures, bilateral removal of temporal lobe
What happened to HM?
Had major seizures since 16yrs and drugs failed to contain seizures. Had surgical removal of anterior hippocampal regions at 27yrs.
What deficits did HM have?
-IQ unaffected by surgery, no personality change or other non-memory deficits. -Deficits in memory restricted to formation of new memories.
How was HM’s working memory still intact?
-Normal digit span unless interrupted but rate of forgetting within normal range, can hold conversation but will forget.
-Semantic memory disrupted and absence of new episodic memory. Eg could not remember events or people post operation.
-Could learn new motor tasks eg mirror tracing task but only improvements in ST but lost progress when pushed to LT.
What are the experimental designs of dissociations?
-Some tasks impaired whilst others spared suggests these tasks use different resources or regions eg semantic dementia patients.
But- maybe one task is more difficult so it will always fail first
What is the neurology of memory and perception?
Patients such as HM suggest the hippocampus does not store memories and that old memories are preserved.
-Role of hippocampus not fully understood but may enable consolidation of new memories, stored elsewhere.
Describe the consolidation process?
Consolidation process may take decades shown by HM in which more distant memories are relatively preserved
What is visual perception?
Within occipital lobes and surrounding temporal and parietal including PVC, ventral and dorsal stream.
What can damage to visual perception systems cause?
Damage to these systems can cause agnosia (damage to ventral) or optic ataxia (damage to dorsal).
What is Agnosia?
Inability to recognise so lack of knowing/recognising.
What is Optic ataxia?
Spatial perception deficits
What is Modality specific agnosia?
Individuals with visual agnosia would be able to name a object through touch.
What are the 2 types of visual agnosia?
Apperceptive
Associative
What is Apperceptive visual agnosia?
Unable to perceive full shape of object despite intact low-level processing. -Inability to extract global structure.
Intact low-level perception- brightness discrimination, colour vision Evidence through impairments in drawing, copying and visual recognition, even of common objects.
What is Associative visual agnosia?
Ability to perceive shape but inability to recognise. -Inability to recognise whole form but no problem copying figures. -Inability to draw from verbal instruction
What is apperceptive prosopagnosia?
Defined as the inability to even perceive and cognitively process faces.
What is Associative prosopagnosia?
Defined as inability to recognize or apply any meaning to the face, despite perceiving it.
Why are faces considered special?
-We are considered experts at processing faces often as they all include same features but configuration is unique to an individual. -Face-processing involves perception of the configuration as well as the features
Why are faces considered difficult to recognise?
Most have difficulty recognizing differences within categories eg types of car, breed of dog, cows in herd.
