Neural correlates of interoceptive accuracy: Beyond cardioception

Interoceptive accuracy (IAc), the precision with which one assesses the signals arising from one's own body, is receiving increasing attention in the literature. IAc has mainly been approached as an individual trait and has been investigated through the cardiac modality using mostly non-ecological methods. Such studies consensually designate the anterior insular cortex as the main brain correlate of IAc. However, there is a lack of brain imaging studies investigating IAc in a broader and more ecological way. Here, we used a novel ecological task in which participants monitored their general bodily reactions to external events and investigated brain regions subtending intraindividual (i.e. trial-by-trial) variations of IAc. At each trial, participants had to rate the intensity of their bodily reactions to an emotional picture. We recorded participants' skin conductance response (SCR) to the picture as an indicator of actual physiological response intensity. We fitted a functional magnetic resonance imaging (fMRI) model using, as regressors, the SCR value, the rating and the product of the two (as a proxy of participants' IAc) obtained trial per trial. We observed that activity in the dorsomedial prefrontal cortex (dmPFC) increased when individuals' IAc decreased. This result reveals general mechanism of error processing in intraindividual variations of IAc, which are unspecific to interoception. Our result has a practical impact in the clinical domain. Namely, it supports the predictive coding framework whereby IAc deficits may reflect impairments in processing a mismatch between actual interoceptive signals and predictions.