Article

The neural correlates of emotion processing have been shown to vary with age:
older adults (OAs) exhibit increased frontal activations and, under some
circumstances, decreased amygdala activations relative to young adults (YAs)
during emotion processing. Some of these differences are additionally modulated
by valence, with age-related biases toward positive versus negative stimuli, and
are thought to depend on OAs' capacity for controlled elaboration. However, the
role of semantic elaboration in mediating valence effects in the aging brain has
not yet been explicitly tested. In the present study, YAs and OAs were scanned
while they viewed negative, neutral, and positive pictures during either a deep,
elaborative task or a shallow, perceptual task. fMRI results reveal that
emotion-related activity in the amygdala is preserved in aging and insensitive to
elaboration demands. This study provides novel evidence that differences in
valence processing are modulated by elaboration: relative to YAs, OAs show
enhanced activity in the medial prefrontal cortex (PFC) and ventrolateral PFC in
response to positive versus negative stimuli, but only during elaborative
processing. These positive valence effects are predicted by individual
differences in executive function in OAs for the deep but not shallow task.
Finally, psychophysiological interaction analyses reveal age effects on
valence-dependent functional connectivity between medial PFC and ventral
striatum, as well as age and task effects on medial PFC-retrosplenial cortex
interactions. Altogether, these findings provide support for the hypothesis that
valence shifts in the aging brain are mediated by controlled processes such as
semantic elaboration, self-referential processing, and emotion regulation.
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Langue : ANGLAIS