Age-Related Differences in Interoceptive Accuracy: A Functional Near-Infrared Spectroscopy (fNIRS) Study

Interoceptive accuracy (IAcc), the objective capacity to sense internal bodily signals, declines with aging, yet its underlying neural mechanisms remain unclear. This study utilized functional near-infrared spectroscopy (fNIRS) to investigate age-related differences in cortical activation and functional connectivity of cortical regions during interoceptive tasks to uncover neural mechanisms that may explain age-related differences in IAcc. This study recruited 29 young adults (M _age =23.76) and 25 older adults (M _age =64.32) to undertake a breath-focused interoceptive task and a resting-state scan. IAcc was assessed by the heartbeat perception task. This study showed that young adults exhibited significantly greater activation in the supplementary motor cortex (SMC), prefrontal cortex (PFC), inferior frontal gyrus (IFG), left primary somatosensory cortex (S1-L), and right primary motor cortex (M1-R) during the interoceptive task compared to older adults. Critically, higher IAcc was positively correlated with the IFG-L activation. Older adults demonstrated significantly stronger functional connectivity between S1-L and IFG-R, PFC-R, as well as PFC-L during the interoceptive task relative to the resting state. Importantly, between-group comparisons revealed a trend enhanced functional connectivity in older adults for M1-L/M1-R, S1-L/IFG-R and PFC networkers before the FDR correction for multiple comparisons. These findings suggest that age-related cortical changes may compromise the neural efficiency of interoceptive networks. This research provides novel insights into the age-specific neural patterns underlying IAcc decline, highlighting potential biomarkers for early identification of interoceptive decline risks and informing the development of targeted interventions to mitigate age-related changes in interoceptive function.