Recent Trends in Non-invasive Neural Recording Based Brain-to-Brain Synchrony Analysis on Multidisciplinary Human Interactions for Understanding Brain Dynamics: A Systematic Review

Abstract

The study of brain-to-brain synchrony has a burgeoning application in the brain-computer interface (BCI) research, offering valuable insights into the neural underpinnings of interacting human brains using numerous neural recording technologies. The area allows exploring the commonality of brain dynamics by evaluating the neural synchronization among a group of people performing a specified task. The growing number of publications on brain-to-brain synchrony inspired the authors to conduct a systematic review using the PRISMA protocol so that future researchers can get a comprehensive understanding of the paradigms, methodologies, translational algorithms, and challenges in the area of brain-to-brain synchrony research. This review has gone through a systematic search with a specified search string and selected some articles based on pre-specified eligibility criteria. The findings from the review revealed that most of the articles have followed the social psychology paradigm, while 36% of the selected studies have an application in cognitive neuroscience. The most applied approach to determine neural connectivity is a coherence measure utilizing phase-locking value (PLV) in the EEG studies, followed by wavelet transform coherence (WTC) in all of the fNIRS studies. While most of the experiments have control experiments as a part of their setup, a small number implemented algorithmic control, and only one study had interventional or a stimulus-induced control experiment to limit spurious synchronization. Hence, to the best of the authors' knowledge, this systematic review solely contributes to critically evaluating the scopes and technological advances of brain-to-brain synchrony to allow this discipline to produce more effective research outcomes in the remote future.

Dual-MEG interbrain synchronization during turn-taking verbal interactions between mothers and children

“…This structured approach allows a moderate level of control. To be noted, this type of seminaturalistic ( Nazneen et al. 2022 ) and quasi-realistic speech interaction is different from natural conversations.…”

Group identity modulates interbrain synchronization during repeated lottery contest.

“…In this study, the interbrain synchronization is measured using PLV, which determines the stability of the phase difference between two signals within a time window of interest. It is also widely used in EEG hyperscanning studies (Nazneen et al, 2022). Relative to other methods, the main advantage of PLV is that its higher temporal resolution and higher sensitivity to phase, making it an ideal for detecting the ever-changing information in interactions.…”

“…In this study, the interbrain synchronization is measured using PLV, which determines the stability of the phase difference between two signals within a time window of interest. It is also widely used in EEG hyperscanning studies (Nazneen et al, 2022).…”

Mobile fNIRS for exploring inter-brain synchrony across generations and time

“…To date, only Duan et al ( 2013 ) have used fNIRS hyperscanning in a neurofeedback paradigm, in which they demonstrate the feasibility of fNIRS in a dual-brain neurofeedback loop. Mobile fNIRS devices have yet to be used in hyperscanning neurofeedback settings, but should ensure participants' comfort and the feasibility of integrating neurofeedback into real world settings and social interactions (Nazneen et al, 2022 ). Given the portability and suitability of mobile fNIRS devices for use with all populations (Ayaz et al, 2022 ), we expect to see more neurofeedback interventions involving two or more brains embedded in the real world, while keeping ethical concerns about the use of such technologies front and center (UNESCO, 2022 ).…”