The congruence of interoceptive predictions and hippocampal-related memory

Interoceptive deficits are associated with medial temporal lobe (MTL) lesions, and especially the hippocampus, which may relate to interoception's reliance upon predictive coding and hence on mnemonic processes. Here, we develop a new task to assess interoceptive predictions and assess their dependence upon MTL memory systems. Healthy participants were asked to imagine and predict what they would feel like across nine interoceptive situations. Later, each situation was physically experienced, and participants reported what they actually felt. An index of predictive congruence was derived and correlated with a neuropsychological measure of hippocampal dependent learning and memory (HDLM), finding that more accurate predictions were associated with better HDLM (Cohen's d = 0.5). We suggest the MTL, and in particular the hippocampus, generates contextually appropriate episodic memories, providing a predictive framework for interpreting afferent bodily neurohormonal signals. The loss of this capacity may account for the profound interoceptive deficits observed following MTL lesions.