Real-time fMRI-triggered experience-sampling: a proof-of-concept study.

A new method called real-time fMRI-triggered experience-sampling (rt-fMRI-ES) was developed to capture spontaneous thoughts with better temporal precision. During a resting state, brain activity in the dorsal anterior insular cortex (part of the salience network) and posteromedial cortex (part of the default mode network) was monitored in real time to trigger thought probes. In 42 to 49 participants, the method did not support the hypothesis that arousal ratings would be higher when triggered by insular activation, but it did support the hypothesis that external-attention ratings were lower when triggered by posteromedial cortex activation. The rt-fMRI-ES technique successfully enables efficient sampling of spontaneous thoughts based on ongoing neural activity.

Study at a glance

Abstract

Much of a typical individual's mental life is characterized by spontaneous thoughts that occur independently of external stimuli. In prior studies, ongoing mental experiences and their neural correlates have been captured using thought probes presented at random intervals during functional Magnetic Resonance Imaging (fMRI). However, this approach results in temporally imprecise estimates of brain activity relative to the arising of mental experience. In this preregistered, proof-of-concept study, we aimed to improve temporal precision using a novel method termed real-time fMRI-triggered experience-sampling (rt-fMRI-ES). We analyzed blood-oxygenation-level-dependent signals in real time during a wakeful resting state (n=60) to trigger thought probes from spontaneous activations within two regions: the dorsal anterior insular cortex (daIC; a key region within salience network) and posteromedial cortex (PMC; a key region within default mode network). We tested two preregistered hypotheses: (H1) Ratings of arousal time-locked to daIC-activation trials are higher than ratings time-locked to non-daIC-activation trials; (H2) Ratings of external-attention time-locked to PMC-activation trials are lower than ratings time-locked to non-PMC-activation trials. After applying preregistered exclusion criteria, 42 participants (1243 trials) and 49 participants (1429 trials) were included in H1 and H2 analyses, respectively. We did not find evidence in support of H1, but we did find evidence in support of H2, as external-attention ratings were significantly lower for trials triggered by PMC activation compared to other trial types. Taken together, we successfully developed and validated the rt-fMRI-ES method, offering a novel technique to efficiently capture spontaneous thoughts based on ongoing neural activity.