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New semantic learning in patients with large medial temporal lobe lesions.
- Source :
-
Hippocampus [Hippocampus] 2008; Vol. 18 (6), pp. 575-83. - Publication Year :
- 2008
-
Abstract
- Two patients with large lesions of the medial temporal lobe were given four tests of semantic knowledge that could only have been acquired after the onset of their amnesia. In contrast to previous studies of postmorbid semantic learning, correct answers could be based on a simple, nonspecific sense of familiarity about single words, faces, or objects. According to recent computational models (for example, Norman and O'Reilly (2003) Psychol Rev 110:611-646), this characteristic should be optimal for detecting the kind of semantic learning that might be supported directly by the neocortex. Both patients exhibited some capacity for new learning, albeit at a level substantially below control performances. Notably, the correct answers appeared to reflect declarative memory. It was not the case that the correct answers simply popped out in some automatic way in the absence of any additional knowledge about the items. Rather, the few correct choices made by the patients tended to be accompanied by additional information about the chosen items, and the available knowledge appeared to be similar qualitatively to the kind of factual knowledge that healthy individuals gradually acquire over the years. The results are consistent with the idea that neocortical structures outside the medial temporal lobe are able to support some semantic learning, albeit to a very limited extent. Alternatively, the small amount of learning detected in the present study could depend on tissue within the posterior medial temporal lobe that remains intact in both patients.<br /> ((c) 2008 Wiley-Liss, Inc.)
- Subjects :
- Aged, 80 and over
Amnesia, Anterograde etiology
Amnesia, Anterograde pathology
Amnesia, Anterograde physiopathology
Encephalitis, Viral complications
Encephalitis, Viral pathology
Entorhinal Cortex pathology
Entorhinal Cortex physiopathology
Face
Hippocampus pathology
Hippocampus physiopathology
Household Articles
Humans
Language Tests
Learning Disabilities etiology
Learning Disabilities pathology
Male
Memory Disorders etiology
Memory Disorders pathology
Mental Recall
Middle Aged
Pattern Recognition, Visual
Prosopagnosia etiology
Prosopagnosia pathology
Prosopagnosia physiopathology
Recognition, Psychology
Temporal Lobe pathology
Learning Disabilities physiopathology
Memory Disorders physiopathology
Temporal Lobe physiopathology
Subjects
Details
- Language :
- English
- ISSN :
- 1098-1063
- Volume :
- 18
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- Hippocampus
- Publication Type :
- Academic Journal
- Accession number :
- 18306299
- Full Text :
- https://doi.org/10.1002/hipo.20417