Agency accounts for the effect of feedback transparency on motor imagery neurofeedback performance

Objective Neurofeedback (NF) is a cognitive training procedure based on real-time feedback (FB) of a participant’s brain activity that they must learn to self-regulate. A classical visual FB delivered in a NF task is a filling gauge reflecting a measure of brain activity. This abstract visual FB is not transparently linked—from the subject’s perspective—to the task performed (e.g., motor imagery). This may decrease the sense of agency, that is, the participants’ reported control over FB. Here, we assessed the influence of FB transparency on NF performance and the role of agency in this relationship. Approach Participants performed a NF task using motor imagery to regulate brain activity measured using electroencephalography. In separate blocks, participants experienced three different conditions designed to vary transparency: FB was presented as either 1) a swinging pendulum, 2) a clenching virtual hand, 3) a clenching virtual hand combined with a motor illusion induced by tendon vibration. We measured self-reported agency and user experience after each NF block. Main results We found that FB transparency influences NF performance. Transparent visual FB provided by the virtual hand resulted in significantly better NF performance than the abstract FB of the pendulum. Surprisingly, adding a motor illusion to the virtual hand significantly decreased performance relative to the virtual hand alone. Self-reported agency accounted for these effects of FB transparency and was significantly associated with NF performance at the within-subject level across all FB types. Significance Our results highlight the relevance of transparent FB in relation to the sense of agency. This factor is likely an important consideration in designing FB, which should be tailored to maximize the sense of agency to improve NF performance and learning outcomes. ### Competing Interest Statement The authors have declared no competing interest.