期刊
NEUROPSYCHOLOGIA
卷 49, 期 3, 页码 392-404出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.neuropsychologia.2010.12.011
关键词
Dementia; Semantic memory; Language; fMRI; Word retrieval; Category-specific deficit
资金
- National Institute on Aging [R01 AG012674, K24 AG026431, P50 AG05131]
- Alzheimer Association [IIRG 07-59343, NIRG-07-59143, NIRG 09-131856]
- VA
- National Institutes of Health [MH18399-20]
- NINDS [F31 NS059193]
Word retrieval deficits are common in Alzheimer's disease (AD) and are thought to reflect a degradation of semantic memory. Yet, the nature of semantic deterioration in AD and the underlying neural correlates of these semantic memory changes remain largely unknown. We examined the semantic memory impairment in AD by investigating the neural correlates of category knowledge (e.g., living vs. nonliving) and featural processing (global vs. local visual information). During event-related fMRI, 10 adults diagnosed with mild AD and 22 cognitively normal (CN) older adults named aloud items from three categories for which processing of specific visual features has previously been dissociated from categorical features. Results showed widespread group differences in the categorical representation of semantic knowledge in several language-related brain areas. For example, the right inferior frontal gyrus showed selective brain response for nonliving items in the CN group but living items in the AD group. Additionally, the AD group showed increased brain response for word retrieval irrespective of category in Broca's homologue in the right hemisphere and rostral cingulate cortex bilaterally, which suggests greater recruitment of frontally mediated neural compensatory mechanisms in the face of semantic alteration. Published by Elsevier Ltd.
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