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Hyperscanning refers to obtaining simultaneous neural recordings from more than one person (Montage et al., 2002), that can be used to study interactive situations. In particular, hyperscanning with Electroencephalography (EEG) is becoming increasingly popular since it allows researchers to explore the interactive brain with a high temporal
resolut...
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Context 1
... The two ANT systems are connected to two different recording computers using USB2 cables. Note that there are two separate data collections running at the same time, so the timing of the triggers/markers is crucial in order to combine and synchronize the two data sets. This is facilitated by a 25-pin serial port y-cable: female/2 male (see Fig. 6) that connects one stimulation computer (with E-prime, Psychtoolbox, or other stimulation software) to both recording computers via amplifiers. The two recording computers thus simultaneously receive the same trigger/marker, which can be used to synchronize the datasets. The impedance measurements and data collection require two ...
Citations
... Two separate 32-channel systems (BioSemi) were used to record EEG with a sampling rate of 512 Hz. The two systems recorded simultaneously using the BioSemi ActiveTwo daisychain mode (see Figure 8 in Barraza et al., 2019). More details are provided in the Supplementary Materials. ...
Coordinating actions with others is thought to require Theory of Mind (ToM): the ability to take perspective by attributing underlying intentions and beliefs to observed behavior. However, researchers have yet to establish a causal role for specific cognitive processes in coordinated action. Since working memory load impairs ToM in single-participant paradigms, we tested whether load manipulation affects two-person coordination. We used EEG to measure P3, an assessment of working memory encoding, as well as inter-brain synchronization (IBS), which is thought to capture mutual adjustment of behavior and mental states during coordinated action. In a computerized coordination task, dyads were presented with novel abstract images and tried selecting the same image, with selections shown at the end of each trial. High working memory load was implemented by a concurrent n-back task. Compared with a low-load control condition, high load significantly diminished coordination performance and P3 amplitude. A significant relationship between P3 and performance was found. Load did not affect IBS, nor did IBS affect performance. These findings suggest a causal role for working memory in two-person coordination, adding to a growing body of evidence challenging earlier claims that social alignment is domain-specific and does not require executive control in adults.
... Recruited mother-infant dyads were invited to come to the Life Span Laboratory for a 1.5-hour visit during which the 30-minute EEG measurements were done. EEG measurements were performed on mothers and their infants using two connected BioSemi Active Two systems with 64 channels (for further information about this hyperscanning set up, please see (Barraza et al., 2019;. The electrodes were placed using the 10-20 system and the sampling rate was set at 512 Hz. ...
Mother-infant interactions form a strong basis for emotion regulation development in infants. These interactions can be affected by various factors, including maternal postnatal anxiety. Electroencephalography (EEG) hyperscanning allows for simultaneous assessment of mother-infant brain-to-behavior association during stressful events, such as the still-face paradigm (SFP). This study aimed at investigating dyadic interactive behavior and brain-to-behavior association across SFP and identifying neural correlates of mother-infant interactions in the context of maternal postnatal anxiety. We measured frontal alpha asymmetry (FAA), a physiological correlate of emotion regulation and a potential marker of risk for psychopathology. To emulate real-life interactions, EEG and behavioral data were collected from 38 mother-infant dyads during a smartphone-adapted dual-SFP. Although the behavioral data showed a clear still-face effect for the smartphone-adapted SFP, this was not reflected in the infant or maternal FAA. Brain-to-behavior data showed higher infant negative affect being associated with more infant leftward FAA during the still-face episodes. Finally, mothers with higher postnatal anxiety showed more right FAA during the first still-face episode, suggesting negative affectivity and a need to withdraw from the situation. Our results form a baseline for further research assessing the effects of maternal postnatal anxiety on infants’ FAA and dyadic interactive behavior.
... Referring to the EEG hyperscanning equipment used by Barraza et al. (2019), two 64-channel SynAmps2 EEG recording systems produced by the Neuroscan Company were used to record the EEG signals of two participants simultaneously. Ground electrode, GND, referred to REF online. ...
Competition is a common occurrence in life, but the influence of intimate relationships on people’s competitiveness remains unknown. Grounded in Darwin’s theory of sexual selection, this study utilized EEG hyperscanning technology to investigate the influence of the presence of romantic partners and the gender of competitors on the interbrain synchronization of female individuals during competitive contexts. The research results showed that in competitive interactions, there was a significant increase in Theta and Alpha frequency band activity between females and their competitors. Interbrain synchronization was strongest when their partners were not nearby and females competed with same gender competitors. The research results indicate that intimate companionship has an impact on the early alertness and late cognitive execution mechanisms of female individuals in competition, and due to intimate relationships, females pay more attention to same-gender competitors. This study demonstrates that the presence of intimate partners can affect a female’s competitive state and brain synchronization with opponents of different genders, improving the theoretical explanation of intimate relationships and competitive interactions.
... In this type of research, the neural data of two (or more) participants is often collected simultaneously via functional nearinfrared spectroscopy (fNIRS), EEG, magnetoencephalography, or Magnetic Resonance Imaging (MRI). In this review, simultaneous acquirement of EEG data, also known as "dual-EEG" or "hyperscanning" (Barraza et al., 2019), will be discussed as a methodological advance that will allow researchers to study the neural dynamics underlying language in more naturalistic contexts. Such dual-EEG data is used to measure inter-brain synchrony as well as intra-brain oscillatory activity while participants are conversing in more naturalistic, rich contexts. ...
How do neural oscillations support human audiovisual language and communication? Considering the rhythmic nature of audiovisual language, in which stimuli from different sensory modalities unfold over time, neural oscillations represent an ideal candidate to investigate how audiovisual language is processed in the brain. Modulations of oscillatory phase and power are thought to support audiovisual language and communication in multiple ways. Neural oscillations synchronize by tracking external rhythmic stimuli or by re-setting their phase to presentation of relevant stimuli, resulting in perceptual benefits. In particular, synchronized neural oscillations have been shown to subserve the processing and the integration of auditory speech, visual speech, and hand gestures. Furthermore, synchronized oscillatory modulations have been studied and reported between brains during social interaction, suggesting that their contribution to audiovisual communication goes beyond the processing of single stimuli and applies to natural, face-to-face communication.
There are still some outstanding questions that need to be answered to reach a better understanding of the neural processes supporting audiovisual language and communication. In particular, it is not entirely clear yet how the multitude of signals encountered during audiovisual communication are combined into a coherent percept and how this is affected during real-world dyadic interactions. In order to address these outstanding questions, it is fundamental to consider language as a multimodal phenomenon, involving the processing of multiple stimuli unfolding at different rhythms over time, and to study language in its natural context: social interaction. Other outstanding questions could be addressed by implementing novel techniques (such as rapid invisible frequency tagging, dual-electroencephalography, or multi-brain stimulation) and analysis methods (e.g., using temporal response functions) to better understand the relationship between oscillatory dynamics and efficient audiovisual communication.
... Software solutions for device synchronization exist (e.g., Lab Streaming Layer) and are being augmented by efforts to provide low-cost hardware solutions (Bilucaglia et al., 2020). This issue is also very important to consider when performing hyper-scanning studies (Babiloni and Astolfi, 2014;Barraza et al., 2019). In addition, precision can be further improved by considering brain time instead of clock time to synchronize neuroscientific measurements between participants according to ongoing oscillatory brain dynamics (van Bree et al., 2022). ...
Human neuroscience has always been pushing the boundary of what is measurable. During the last decade, concerns about statistical power and replicability - in science in general, but also specifically in human neuroscience - have fueled an extensive debate. One important insight from this discourse is the need for larger samples, which naturally increases statistical power. An alternative is to increase the precision of measurements, which is the focus of this review. This option is often overlooked, even though statistical power benefits from increasing precision as much as from increasing sample size. Nonetheless, precision has always been at the heart of good scientific practice in human neuroscience, with researchers relying on lab traditions or rules of thumb to ensure sufficient precision for their studies. In this review, we encourage a more systematic approach to precision. We start by introducing measurement precision and its importance for well-powered studies in human neuroscience. Then, determinants for precision in a range of neuroscientific methods (MRI, M/EEG, EDA, Eye-Tracking, and Endocrinology) are elaborated. We end by discussing how a more systematic evaluation of precision and the application of respective insights can lead to an increase in reproducibility in human neuroscience.
... The desired mBCI system should provide high-quality EEG signals to guarantee its reliability and robustness when facing diverse ambient noise. Second, the traditional fixed-linked EEG devices are connected by cables to form a multi-subject acquisition system (Barraza et al., 2019). This fixed-linked system imposes limitations on subjects' range of motion and activities, consequently affecting their overall user experience and restricting the wider application of mBCI. ...
... Among all EEG systems, Emotiv is the most commonly used wearable system in research studies (Roy et al., 2019), whereas Brain Products, EGI, BIOSEMI, and g.Tec are the most frequently used desktop systems in hyperscanning studies (Barraza et al., 2019). ...
Objective
The multi-subject brain–computer interface (mBCI) is becoming a key tool for the analysis of group behaviors. It is necessary to adopt a neural recording system for collaborative brain signal acquisition, which is usually in the form of a fixed wire.
Approach
In this study, we designed a wireless group-synchronized neural recording system that supports real-time mBCI and event-related potential (ERP) analysis. This system uses a wireless synchronizer to broadcast events to multiple wearable EEG amplifiers. The simultaneously received broadcast signals are marked in data packets to achieve real-time event correlation analysis of multiple targets in a group.
Main results
To evaluate the performance of the proposed real-time group-synchronized neural recording system, we conducted collaborative signal sampling on 10 wireless mBCI devices. The average signal correlation reached 99.8%, the amplitude of average noise was 0.87 μV, and the average common mode rejection ratio (CMRR) reached 109.02 dB. The minimum synchronization error is 237 μs. We also tested the system in real-time processing of the steady-state visual-evoked potential (SSVEP) ranging from 8 to 15.8 Hz. Under 40 target stimulators, with 2 s data length, the average information transfer rate (ITR) reached 150 ± 20 bits/min, and the highest reached 260 bits/min, which was comparable to the marketing leading EEG system (the average: 150 ± 15 bits/min; the highest: 280 bits/min). The accuracy of target recognition in 2 s was 98%, similar to that of the Synamps2 (99%), but a higher signal-to-noise ratio (SNR) of 5.08 dB was achieved. We designed a group EEG cognitive experiment; to verify, this system can be used in noisy settings.
Significance
The evaluation results revealed that the proposed real-time group-synchronized neural recording system is a high-performance tool for real-time mBCI research. It is an enabler for a wide range of future applications in collaborative intelligence, cognitive neurology, and rehabilitation.
... Following the procedures described in Barraza et al. (2019) for the implementation of the EEG hyperscanning setup, The EEG signals were recorded using the 64-channel EEG recording system produced by Neuroscan, and the EEG signals of two subjects were recorded simultaneously using two 64channel SynAmps 2, and then connected to an ampli er through a separate head box. ...
Interbrain synchronization is considered the foundation of consciousness. When people jointly complete a social interaction, there is an inevitable overlap in their cognitive activities; brain synchronization is also considered a sign of individuals completing social interaction together. Based on Darwin's sexual selection theory, this study explored the influence of intimate relationship lover's companionship on female individual competitive interaction and peer brain coupling with competitors through EEG hyperscanning technology, using visual cue-target paradigm and taking inter-brain synchronized phase lock value (PLV) as a measurement index. The research results showed that in competitive interactions, there is a significant increase in theta and alpha frequency band activity between women and their competitors' brains. Brain synchronization is strongest when lovers are not around and women compete with same-sex competitors. In addition, there was a significant negative correlation between brain synchronization and behavioral DRT. The research results indicate that intimate companionship impacts the early alertness and late cognitive execution mechanisms of female individuals in competition. Women tend to focus on competitive tasks when their partner is not around. Moreover, due to intimate relationships, women in the romantic group pay less attention to opposite-sex competitors, while they pay more attention to same-sex competitors. This study demonstrates the impact of intimate relationship partner companionship status and opponent gender on individual female competition and improves the theoretical explanation of intimate relationships and competitive interaction.
... Their EEG signals were recorded using two individual EEG preamplifiers and amplifiers (g.USBamp, g.tec Inc., Schiedlberg, Austria) separately. Our method of recording EEG data was similar to that used in the previous study [27]. A trigger signal was input to both EEG amplifiers by the experimenter's button press to record the start and end times of the task to keep the two EEG signals temporally synchronized. ...
Mixed-reality (MR) environments, in which virtual objects are overlaid on the real environment and shared with peers by wearing a transparent optical head-mounted display, are considered to be well suited for collaborative work. However, no studies have been conducted to provide neuroscientific evidence of its effectiveness. In contrast, inter-brain synchronization has been repeatedly observed in cooperative tasks and can be used as an index of the quality of cooperation. In this study, we used electroencephalography (EEG) to simultaneously measure the brain activity of pairs of participants, a technique known as hyperscanning, during a cooperative motor task to investigate whether inter-brain synchronization would be also observed in a shared MR environment. The participants were presented with virtual building blocks to grasp and build up an object cooperatively with a partner or individually. We found that inter-brain synchronization in the cooperative condition was stronger than that in the individual condition (F(1, 15) = 4.70, p < 0.05). In addition, there was a significant correlation between task performance and inter-brain synchronization in the cooperative condition (rs = 0.523, p < 0.05). Therefore, the shared MR environment was sufficiently effective to evoke inter-brain synchronization, which reflects the quality of cooperation. This study offers a promising neuroscientific method to objectively measure the effectiveness of MR technology.
... This makes it easy to apply 32 electrodes to the head of each participant. It should be noted that in a review of using different EEG hardware for hypersacnning studies, Barraza and colleagues [4] noted that, "Brain Products setup using actiCHamp is not described since this amplifier was not explicitly designed for EEG hyperscanning " (p. 346), noting that by default all channels share the same ground, so that noise specific to each individual participant cannot be isolated and removed. ...
EEG hyperscanning refers to recording electroencephalographic (EEG) data from multiple participants simultaneously. Many hyperscanning experimental designs seek to mimic naturalistic behavior, relying on unpredictable participant-generated stimuli. The majority of this research has focused on neural oscillatory activity that is quantified over hundreds of milliseconds or more. This contrasts with traditional event-related potential (ERP) research in which analysis focuses on transient responses, often only tens of milliseconds in duration. Deriving ERPs requires precise time-locking between stimuli and EEG recordings, and thus typically relies on pre-set stimuli that are presented to participants by a system that controls stimulus timing and synchronization with an EEG system. EEG hyperscanning methods typically use separate EEG amplifiers for each participant, increasing cost and complexity — including challenges in synchronizing data between systems. Here, we describe a method that allows for simultaneous acquisition of EEG data from a pair of participants engaged in conversation, using a single EEG system with simultaneous audio data collection that is synchronized with the EEG recording. This allows for the post-hoc insertion of trigger codes so that it is possible to analyze ERPs time-locked to specific events. We further demonstrate methods for deriving ERPs elicited by another person's spontaneous speech, using this setup. • EEG hyperscanning method using a single EEG amplifier • EEG hyperscanning method allowing simultaneous recording of audio data directly into the EEG data file for perfect synchronization • EEG method for naturalistic language and human interaction studies that allows the study of event-related potentials time-locked to spontaneous speech
... We followed the recommended dual-EEG setup and procedures described in (Barraza et al., 2019) and recorded the EEG signals of the two participants simultaneously from 32 AG-AgCI electrodes, of which 27 were mounted in a cap (actiCap) according to the 10-20 standard system. One electrode was placed on the right mastoid for re-referencing, and 4 were used for bipolar horizontal and vertical electrooculograms (EOG). ...
We here demonstrate that face-to-face spatial orientation induces a special ‘social mode’ for neurocognitive processing during conversation, even in the absence of visibility. Participants conversed face to face, face to face but visually occluded, and back to back to tease apart effects caused by seeing visual communicative signals and by spatial orientation. Using dual EEG, we found that (1) listeners’ brains engaged more strongly while conversing face to face than back to back, irrespective of the visibility of communicative signals, (2) listeners attended to speech more strongly in a back-to-back compared to a face-to-face spatial orientation without visibility; visual signals further reduced the attention needed; (3) the brains of interlocutors were more in sync in a face-to-face compared to a back-to-back spatial orientation, even when they could not see each other; visual signals further enhanced this pattern. Communicating in face-to-face spatial orientation is thus sufficient to induce a special ‘social mode’ which fine-tunes the brain for neurocognitive processing in conversation.
