Affiliations: Psychology Department, University of Milano-Bicocca,
Milano, Italy | Cognitive Neuropsychology Laboratory, Niguarda Ca'
Granda Hospital, Milano, Italy | Psychology Department, University of Pavia, Pavia,
Italy | Clinical Neuroscience Department, Niguarda Ca' Granda
Hospital, Milano, Italy | Neuroradiology Department, Niguarda Ca' Granda
Hospital, Milano, Italy
Abstract: In 2000 Baddeley proposed the existence of a new component of
working memory, the episodic buffer, which should contribute to the on-line
maintenance of integrated memory traces. The author assumed that this component
should be critical for immediate recall of a short story that exceeds the
capacity of the phonological store. Accordingly, patients with Alzheimer's
dementia (AD) should suffer of a deficit of the episodic buffer when immediate
recall of a short story is impossible. On the other hand, the episodic buffer
should be somewhat preserved in such patients when some IR can occur (Baddeley
and Wilson, 2002). We adopted this logic for a voxel-based morphometry study. We
compared the distribution of grey-matter density of two such groups of AD
patients with a group of age-matched controls. We found that both AD
groups had a significant atrophy of the left mid-hippocampus; on the other
hand, the anterior part of the hippocampus was significantly more atrophic in
patients who were also impaired on the immediate prose recall task. Six out of
ten patients with no immediate recall were spared at "central executive" tasks.
Taken together our findings suggest that the left anterior hippocampus
contributes to the episodic buffer of the revised working memory model. We also
suggest that the episodic buffer is somewhat independent from the central
executive component of working memory.
