Introspection in neurofeedback performance via neurofeedback training of the insula - A feasibility study

Through real-time functional MRI neurofeedback training individuals can learn the voluntary regulation of a selected neural signal. However, it is unknown whether they have introspection in this targeted neural signal. We performed a feasibility study of a new insula-targeted neurofeedback paradigm, aimed at addressing the question of introspective abilities. Specifically, we tested the feasibility of (1) a heartbeat-counting task to localize the insula, (2) graded neurofeedback of the insula, and (3) participants' ability to estimate the level of activation of the target area. Ten healthy volunteers performed three neurofeedback sessions. Each session started with a heartbeat-counting (interoception) task, as a functional localizer of the insula. Next, a graded neurofeedback task was performed, in which participants were asked to activate the insula to a medium or high target level. After the participant estimated the achieved activity level, feedback was presented. We found (1) significant activation of the insula in the localizer in response to the interoceptive task (2) and increased activity in this target area during regulation, but without activity difference between both regulation levels. There was (3) a small association between estimated and actual activity levels but no improvement in introspective accuracy over the three sessions. These results show good feasibility of the interoceptive-based functional localizer procedure for the insula. Moreover, insula upregulation was achieved in the neurofeedback task, although not in a graded fashion. No clear evidence for introspection was found for the insula.