Age-related neural inefficiency: fNIRS evidence of prefrontal hyperactivation during emotional response inhibition
摘要
Older adults often exhibit reduced inhibitory control accompanied by altered recruitment of prefrontal networks. Whether the emotional context changes these age-related neural patterns during response inhibition remains unclear. In this study, 31 older adults and 19 young adults completed four blocks of a Go/No-Go paradigm while bilateral prefrontal cortex (PFC) activity was recorded using functional near-infrared spectroscopy (fNIRS). Blocks 1 and 2 comprised a neutral (non-emotional) Go/No-Go task using geometric shapes, while blocks 3 and 4 comprised an emotional Go/No-Go task using facial expressions (happy or angry as Go; neutral as No-Go). Task-evoked oxygenated (HbO) and deoxygenated hemoglobin (HbR) responses were quantified and analyzed at both the region-of-interest (ROI) and channel levels using linear mixed-effects models. Behaviorally, older adults showed markedly lower No-Go accuracy than young adults (p < 0.001), and emotional blocks further reduced the accuracy in both groups (p < 0.001). Crucially, reaction time analyses revealed a significant group × condition interaction (p < 0.001): young adults exhibited strategic slowing in the emotional condition, whereas older adults failed to modulate their response speed. Neurally, ROI analyses revealed robust main effects of group (older > young) and condition (emotional < neutral) on HbO across dorsolateral, dorsomedial, and ventromedial ROIs after false discovery rate correction, whereas group × condition interactions were not significant. Brain-behavior analyses revealed that higher prefrontal activation in older adults significantly predicted a poorer performance, supporting a neural inefficiency account. Translationally, these findings suggest that portable fNIRS measures of PFC inefficiency may serve as a scalable biomarker to identify older adults at risk for inhibitory-control failures—especially when emotion is present—and to track neural targets and treatment response in cognitive or emotion-regulation interventions.