Chapter 7 Flashcards
Amnesia
name given to disorders of memory: A pathological impairment of memory function.
Two main groups of amnesia aetiologies
Organic amnesias and psychogenic amnesias
Organic amnesia
caused by physical damage (lesions), like brain infections, strokes, head injuries, and degenerative disorders like Alzheimer -> often irreversible
Psychogenic amnesia
A memory impairment of psychological origin: usually involve the temporary suppression of disturbing memories which are unacceptable to the patient at some level -> reversible and in most cases will eventually disappear
Alzheimer’s disease (AD)
A degenerative brain disorder usually (but not always) afflicting the elderly , which first appears as an impairment of memory but later develops into a more general dementia
Facts to Alzheimer’s disease
most common cause of amnesia, main cause of senile dementia, 20% of elderly people affected. In younger people called pre-senile dementia.
Korsakoff syndrome
A brain disease which usually results from chronic alcoholism, and which is mainly characterised by a memory impairment. Both recent and distant past affected.
Herpes simplex encephalitis (HSE)
A virus infection of the brain, which in some cases leaves the patient severely amnesic. Rare. Sudden onset
Post-ECT amnesia
amnesia through EC therapy
What kind of memory is more often impaired after organic amnesia, long- or short-term memory?
Long-term memory. Short-term is fairly intact.
What part of the WM model is often impaired in severe cases of AD patients
the central executive
Anterograde amnesia (AA)
Impaired memory for events which have occurred since the onset of the disorder
Retrograde amnesia (RA)
Impaired memory for events which occurred prior to the onset of amnesia
possible difference between learning disorders and retrieval disorders
disorder of learning: have AA but not RA
retrieval disorders: Have RA but not AA
Ribot’s law
The observation that amnesic patients show a temporal gradient for retrograde amnesia, early memories are often better present than more recent
Most amnesics exhibit both AA and RA, but there are also patients with a focal AA and focal RA, what does it mean?
focal AA: AA without RA
focal RA: RA without AA -> super rare, just in some cases of HSE infection and following epileptic seizure
Hippocampus
A structure lying within the temporal lobes, which is involved in the creation of new memories. Hippocampal lesions usually cause impairment of memory, especially the storage of new memories.
Diencephalon
A brain structure wich includes the thalamus and hypthalamus. Parts of the diencephalon are involved in processing and retrieving memories, and damage to these structures can cause amnesia
Extended hippocampal complex
A system of interconnected structures within the brain, incorporating the hippocampus, anterior thalamus and mammillary bodies, which is involved in the encoding and storage of new memory traces.
What kind of memories are impaired in most amnesia patients? Procedural, declarative, explicit or implicit memory?
Declarative and explicit memory.
Procedural memory
Memory which can be demonstrated by performing some skilled procedure such as a motor task, but which the subject is not necessarily able to report consciously.
Declarative memory
Memory which
can be reported in
a deliberate and
conscious way
What is impaired in organic amnesics? Familiarity or context recollection?
Context recollection is impaired. Are not aber to say in which context they encountered a familiar object. Maybe a small impairment in familiarity, but it is debated.
What is impaired? Episodic or semantic memory?
Korsakoffs and HSE amnesics are impaired in both (not able to learn new vocabulary). Also Alzheimers both, but episodic more severe -> Let’s say all semantic memory from before the lesion is relatively unimpaired, but still way worth than in healthy people. Some people with just lesion to hippocampus have exclusive “episodic amnesia”, with lesion to anterior temporal lobe you get “semantic amnesia”