Shaping Inter-Brain Plasticity: A Feasibility Study of Enhancing Inter-Brain Synchrony with Dyadic Neurofeedback
Description
This study tested whether dyadic neurofeedback training can causally enhance inter-brain synchrony in the inferior frontal gyrus (IFG) and whether such neural changes translate into increased social connectedness and empathy. We hypothesized that (1) participants receiving real-time neurofeedback would exhibit greater IFG synchrony across sessions compared to a sham-feedback control group; (2) enhanced synchrony would lead to increased feelings of connectedness; (3) increases in inter-brain synchrony would also be associated with intra-brain synchrony changes within individuals. Data Collection: Participants (N=92; 46 dyads) were randomly assigned to an experimental or control group and engaged in three neurofeedback training sessions over one week. fNIRS data were collected simultaneously from both participants using NIRx systems targeting frontal and parietal regions. Real-time coherence in the IFG (oxygenated hemoglobin) was computed using Wavelet Transform Coherence (WTC), and used to drive a visual feedback task (a fish whose speed reflected neural synchrony). The control group received sham feedback. Offline preprocessing and WTC analyses were later conducted on all channels to assess inter- and intra-brain synchrony. Behavioral data were gathered through self-report questionnaires measuring state connectedness (pre/post each session). Findings: The experimental group exhibited a progressive increase in IFG inter-brain synchrony across sessions, whereas the control group did not. Synchrony increases extended to other brain areas, including the IPL and DLPFC. Moreover participants receiving real feedback showed greater improvements in social connectedness, especially in feelings of understanding, identification, and desire to know their partner better. Changes in frontoparietal inter-brain synchrony predicted increases in connectedness in the experimental group. Finally enhanced inter-brain synchrony was associated with increased intra-brain synchrony (especially IFG-IPL and DLPFC pathways), suggesting neuroplastic changes within individuals. In contrast, the control group showed a shift toward increased mPFC-DLPFC with IPL synchrony, possibly reflecting effortful or compensatory processing. Interpretation and Use: The data suggest that inter-brain synchrony is a plastic and trainable neural mechanism. Repeated real-time neurofeedback targeting IFG synchrony can enhance both inter and intra brain synchrony. Inter-brain synchrony was not only upregulated in targeted regions but spread to broader social-cognitive networks, supporting its causal role in social bonding. Moreover, synchronization effects were predictive of behavioral gains, linking neural coordination to social outcomes.
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Institutions
- University of Haifa