CLS Speaker Series - Avery Rizio (Penn State University) Age differences in language production: The neural correlates of semantic interference, phonological facilitation, and target picture frequency
Mar 25, 2016
from 09:00 AM to 10:30 AM
|Where||127 Moore Building|
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Research indicates that picture naming is facilitated when targets are presented with phonologically related words, but slowed by semantically related distractors. Older adults often show declines in phonological aspects of language production, particularly for low frequency words, but maintain strong semantic systems. Here we used fMRI and behavioral measures to investigate age differences as a function of distractor type and target frequency (N=20 younger, 20 older adults). Older adults recruited more activation in left occipital fusiform gyrus and inferior and middle temporal gyri during picture naming with semantically-related distractors compared to phonologically-related distractors. Activation in the occipital fusiform gyrus was significantly greater for older compared to younger adults. Older adults also recruited more activation in left superior parietal lobe during naming with semantic compared to unrelated distractors, though this activation pattern was not different from that of younger adults. Age differences emerged when comparing phonological to categorical distractors, as younger adults showed greater activation than older adults in left postcentral and right precentral gyri. With respect to the effect of target frequency, older adults showed greater negative correlations than younger adults. Specifically, older adults showed increased activation in right precentral and left supramarginal gyri during naming of low frequency items when paired with phonological distractors. These results indicate that the presence of phonological distractors facilitated picture naming in older adults for low frequency targets. The presence of a phonological distractor may increase activation in regions that support motor planning, potentially aiding articulation for words that are most difficult to produce.