Construction of a fiber-optically connected MEG hyperscanning system for recording brain activity during real-time communication

Abstract

Communication is one of the most important abilities in human society, which makes clarification of brain functions that underlie communication of great importance to cognitive neuroscience. To investigate the rapidly changing cortical-level brain activity underlying communication, a hyperscanning system with both high temporal and spatial resolution is extremely desirable. The modality of magnetoencephalography (MEG) would be ideal, but MEG hyperscanning systems suitable for communication studies remain rare. Here, we report the establishment of an MEG hyperscanning system that is optimized for natural, real-time, face-to-face communication between two adults in sitting positions. Two MEG systems, which are installed 500m away from each other, were directly connected with fiber optic cables. The number of intermediate devices was minimized, enabling transmission of trigger and auditory signals with almost no delay (1.95–3.90 μs and 3 ms, respectively). Additionally, video signals were transmitted at the lowest latency ever reported (60–100 ms). We furthermore verified the function of an auditory delay line to synchronize the audio with the video signals. This system is thus optimized for natural face-to-face communication, and additionally, music-based communication which requires higher temporal accuracy is also possible via audio-only transmission. Owing to the high temporal and spatial resolution of MEG, our system offers a unique advantage over existing hyperscanning modalities of EEG, fNIRS, or fMRI. It provides novel neuroscientific methodology to investigate communication and other forms of social interaction, and could potentially aid in the development of novel medications or interventions for communication disorders.

Revealing the Neurobiology Underlying Interpersonal Neural Synchronization with Multimodal Data Fusion

“…181,182 The indirect nature of our evidence for INS mediation by GABAergic signaling and E/I balance requires thorough confirmation or falsification with experimental data. Future electrophysiological, and especially magnetoencephalography-based 183 hyperscanning experiments could investigate the role of E/I balance in the development of INS. GABAergic involvement as well as regulatory mechanisms could be tested using pharmacological challenges with safe oxytocin-regulating or GABA-regulating agents or multibrain stimulation protocols to show causal roles in the regulation and maintenance of human INS.…”

Magnetoencephalography Hyperscanning Evidence of Differing Cognitive Strategies Due to Social Role During Auditory Communication

“…The latency between Piezo sensor activation and audio output was manually set to 18.7 ms, a time which simultaneously did not burden the processing speed of the PC used, and permitted natural musical performance by the subject. Site-to-site audio latency of the MEG hyperscanning system has been evaluated at 3.13 ms in one direction and 2.78 ms in the other direction, with no jitter ( Watanabe et al, 2022 ). The difference in latency depending on the site is thought to reflect the slight difference in distance of the electrostatic speaker in the shielded room to the device helmet.…”

Disorganized Communication and Social Dysfunction in Schizophrenia: Emerging Concepts and Methods

“…Notably, the brain-tobrain entrainment indexed by IBS appears to be independent of shared confounds, such as the physical properties of speech [82]. Magnetoencephalography (MEG), which has a higher spatial resolution than EEG [83], has also been used in a hyperscanning context in healthy individuals, permitting evaluation of IBS during real-time verbal communication [84][85][86] and motor coordination [87]. The low mobility of conventional MEG systems limits the range of naturalistic paradigms employed.…”