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Abstract:
The fact that patients with bilateral hippocampal damage
often show better recall of distant memories compared to more
recent personal events has been cited as evidence that the
hippocampal complex plays a early, and temporary, role in the
retrieval of episodic memories. Further support for this view comes
from studies of remote memory in patients with the
neurodegenerative disease, semantic dementia, in which there is
early sparing of the hippocampal complex in the context of focal
atrophy to other temporal lobe regions. Patients with semantic
dementia show better retrieval of recent autobiographical memories
compared to those from the more distant past. An alternative theory
proposes, however, that the hippocampus is important for the
retrieval of all personal memories, regardless of their age.
Further investigations of remote autobiographical memory in
semantic dementia, and in patients with the frontal variant of
fronto-temporal dementia, tested whether the pattern seen in
semantic dementia was due to one or more of the following factors:
(1) the reported patients are exceptional in their presentation;
(2) impaired strategic retrieval due to concomitant frontal damage;
and (3) linguistic deficits with accompanying preserved non-verbal
access to autobiographical memory. These studies provide strong
support for the view that the original pattern seen in semantic
dementia is not artefactual.
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