Self-Modulation of Premotor Cortex Interhemispheric Connectivity in a Real-Time Functional Magnetic Resonance Imaging Neurofeedback Study Using an Adaptive Approach

Recent studies have reported on the feasibility of real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback (NF) training. Although modulation of blood oxygenation level-dependent signal of single brain regions in rt-fMRI NF is a well established technique, the same does not hold true for modulation of connectivity. Self-modulation of interregional connectivity is a potential alternative in clinical neuroscience applications, since long-range functional dysconnectivity is being increasingly recognized as a mechanism underlying neuropsychiatric disorders. In this study, a framework was designed to train participants to self-regulate, in real time, interhemispheric functional connectivity between bilateral premotor cortices. To this end, participants use a novel adaptive motor imagery task, with gradual frequency variation preventing activity plateaus and subsequent decreases in correlation of activity (three NF runs). Participants were able to upregulate and maintain interhemispheric connectivity using such adaptive approach, as measured by correlation analysis. Modulation was achieved by simultaneous volitional control of activity in premotor areas. Activation patterns in the downregulation condition led to significantly lower correlation values than those observed in the upregulation condition, in the first two NF runs. Comparison between runs with and without feedback showed enhanced activation in key reward, executive function, and cognitive control regions, suggesting NF promotes reward and the development of goal-directed behavior. This proof-of-principle study suggests that functional connectivity feedback can be used for volitional self-modulation of neuronal connectivity. Functional connectivity-based NF could serve as a possible therapeutic tool in diseases related to the impairment of interhemispheric connectivity, particularly in the context to motor training after stroke.