Influence of age on the dynamics of fMRI activations during a semantic fluency task

Age-related fMRI changes have not been extensively studied for language, whereas important adaptive mechanisms have been seen in other cognitive fields. This study examined age-related changes in fMRI activation during language tasks and, in particular, their dynamic course.

fMRI was performed on 22 young and 21 old healthy right-handed subjects during a silent category word-generation task. Activation and dynamics of BOLD signals were studied separately during the first and second portions of each 30-s block.

Activation of the left frontal lobe was initially similar in young and old participants; however, it decreased after 30 s in the old participants. On the other hand, additional areas were initially involved only in old subjects and especially in the default mode network.

This study showed age-related differences in the dynamics of fMRI activation during a silent word-generation task, suggesting a different pattern of language function with aging.