Altered brain response for semantic knowledge in Alzheimer's disease

▶ We examined the semantic memory impairment in Alzheimer's disease (AD). ▶ Using fMRI, we investigated the neural correlates of category knowledge in AD. ▶ Neural correlates of semantic knowledge are altered in AD. ▶ Increased frontal brain response to picture naming in AD suggests compensation. ▶ Differences in brain response to category suggest a graded semantic deficit in AD.