Article

In humans lacunar infarcts in the mesial and anterior regions of the thalami are
frequently associated with amnesic syndromes.
In this review paper, we
scrutinized 41 papers published between 1983 and 2009 that provided data on a
total of 83 patients with the critical ischemic lesions (i.e. 17 patients with
right-sided lesions, 25 with left-sided lesions and 41 with bilateral lesions).
We aimed to find answers to the following questions concerning the vascular
thalamic amnesia syndrome: (i) Which qualitative pattern of memory impairment
(and associated cognitive and behavioral deficits) do these patients present?
(ii) Which lesioned intrathalamic structures are primarily responsible for the
amnesic syndrome? (iii) Are the recollection and familiarity components of
declarative memory underlain by the same or by different thalamic structures?
Results of the review indicate that, similar to patients with amnesic syndromes
due to mesio-temporal lobe damage, patients with vascular thalamic amnesia
display a prevalent deficit of declarative anterograde long-term memory, a less
consistent deficit of declarative retrograde long-term memory and substantially
spared short-term and implicit memory. Unlike mesio-temporal lobe patients,
however, vascular thalamic amnesics often present dysexecutive and behavioral
deficits similar to those observed in patients with frontal damage. The presence
of an amnesic syndrome in patients with thalamic lacunar infarcts is strongly
predicted by involvement of the mammillo-thalamic tract, which connects the
anterior nuclei complex to the hippocampus proper via the fornix and the
mammillary bodies. Finally, data reported in a few single cases provide support
for the hypothesis that thalamic regions connected to distinct areas of the
mesio-temporal lobe play differential roles in recollection and familiarity
processes. The mammillo-thalamic tract/anterior nuclei axis seems primarily
implicated in recollective processes, whereas the ventroamygdalofugal
pathway/medio-dorsal axis primarily underlies familiarity processes.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS