Abstract
BACKGROUND: Real-time functional MRI feedback (RTfMRIf) is a developing technique, with unanswered methodological questions. Given a delay of seconds between neural activity and the measurable hemodynamic response, one issue is the optimal method for presentation of neurofeedback to subjects. The primary objective of this preliminary study was to compare the methods of continuous and intermittent presentation of neural feedback on targeted brain activity. METHODS: Thirteen participants performed a motor imagery task and were instructed to increase activation in an individually defined region of left premotor cortex using RTfMRIf. The fMRI signal change was compared between real and false feedback for scans with either continuous or intermittent feedback presentation. RESULTS: More individuals were able to increase their fMRI signal with intermittent feedback, while some individuals had decreased signal with continuous feedback. The evaluation of feedback itself activated an extensive amount of brain regions, and false feedback resulted in brain activation outside of the individually defined region of interest. CONCLUSIONS: As implemented in this study, intermittent presentation of feedback is more effective than continuous presentation in promoting self-modulation of brain activity. Furthermore, it appears that the process of evaluating feedback involves many brain regions that can be isolated using intermittent presentation.