Brain regions for word retrieval and speech production, and impact of aging

摘要

A PET activation study was conducted to young and elderly subjects to elucidate mechanisms of word finding difficulty in elderly people. Scans were made while the subjects were speaking aloud as many words in specified semantic or phonemic categories as possible. In the young subjects, the left anterior temporal lobe and the frontal pole were activated in the proper-noun fluency task, whereas the left infero-posterior temporal and frontal regions were activated in the remaining semantic (animate and inanimate) and syllable fluency tasks. The elderly subjects revealed different activation patterns from those of the young subjects: some areas were common in the both groups and others were not. In addition, the bilateral cerebellum, which was silent in the young subjects, was active in the syllable fluency task. This was considered as activity to compensate for deficient word retrieval in the elderly.