Mobile brain imaging in butoh dancers: from rehearsals to public performance

BMC Neuroscience Theofanopoulou et al. BMC Neuroscience (2024) 25:62 https://doi.org/10.1186/s12868-024-00864-1 Open Access RESEARCH Mobile brain imaging in butoh dancers: from rehearsals to public performance Constantina Theofanopoulou1,2*, Sadye Paez1,2*, Derek Huber3, Eric Todd3, Mauricio A. Ramírez-Moreno3,4, Badie Khaleghian5, Alberto Muñoz Sánchez1,6, Leah Barceló7, Vangeline Gand8 and José L. Contreras-Vidal3* Abstract Background Dissecting the neurobiology of dance would shed light on a complex, yet ubiquitous, form of human communication. In this experiment, we sought to study, via mobile electroencephalography (EEG), the brain activity of five experienced dancers while dancing butoh, a postmodern dance that originated in Japan. Results We report the experimental design, methods, and practical execution of a highly interdisciplinary project that required the collaboration of dancers, engineers, neuroscientists, musicians, and multimedia artists, among others. We explain in detail how we technically validated all our EEG procedures (e.g., via impedance value monitoring) and minimized potential artifacts in our recordings (e.g., via electrooculography and inertial measurement units). We also describe the engineering details and hardware that enabled us to achieve synchronization between signals recorded at different sampling frequencies, along with a signal preprocessing and denoising pipeline that we used for data re-sampling and power line noise removal. As our experiment culminated in a live performance, where we generated a real-time visualization of the dancers’ interbrain synchrony on a screen via an artistic brain-computer interface, we outline all the methodology (e.g., filtering, time-windows, equation) we used for online bispectrum estimations. Additionally, we provide access to all the raw EEG data and codes we used in our recordings. We, lastly, discuss how we envision that the data could be used to address several hypotheses, such as that of interbrain synchrony or the motor theory of vocal learning. Conclusions Being, to our knowledge, the first study to report synchronous and simultaneous recording from five dancers, we expect that our findings will inform future art-science collaborations, as well as dance-movement therapies. Keywords Electroencephalography, Dance, Butoh, Hyperscanning, Interbrain synchrony, Dance therapy, Interdisciplinarity, Brain-computer interface *Correspondence: Constantina Theofanopoulou Sadye Paez José L. Contreras-Vidal 1 The Rockefeller University, New York, USA 2 Center for the Ballet and the Arts, New York University, New York, USA NSF IUCRC BRAIN Center, University of Houston, Houston, TX, USA Mechatronics Department, School of Engineering and Sciences, Tecnológico de Monterrey, Monterrey, Mexico 5 Rice University, Houston, TX, USA 6 Howard Hughes Medical Institute, Chevy Chase, MD, USA 7 Barnand College, Columbia University, New York, USA 8 New York Butoh Institute, New York, USA 3 4 © The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Theofanopoulou et al. BMC Neuroscience (2024) 25:62 Background Background information on the brain architecture of dance In the past two decades, there has been a mounting interest in identifying the neural underpinnings of artistic expression, and of dance, in particular. The first endeavors towards this direction have focused on studying the brain responses during dance observation, namely while dancers, or non-dancers, perceive videos of dance movements of themselves or others. Brain perception signals have been studied for a variety of dance genres, including but not limited to jazz [1], ballet [2, 3], and tango [4], using either electroencephalography (EEG) [1, 3, 4] or functional magnetic resonance imaging (fMRI) [2]. Overall, their findings underscore the power of both techniques to capture distinct patterns that distinguish dance perception, in an array of settings, such as dance perception by expert dancers vs. non-dancers. Identifying the neural basis of dance performance, involving the actual production of dance movements, has proven challenging, considering the limitations of neuroimaging techniques that render natural movement in space impractical. Still, researchers have come up with creative ideas to address this question. For instance, Brown et al. [5]. used an inclined surface in front of the leg room of a positron emission tomography (PET) scanner, where amateur dancers performed small-scale, cyclic leg tango steps while in a supine position. The same group used fMRI to study bimanual partnered movements, with the experimenter sitting next to the reclined subject holding hands, and alternating between “leading” and “following” joint movements, similar to those used in tango or salsa [6]. In turn, mobile EEG techniques, complemented with motion sensing, have enabled researchers to study brain activity while subjects are dancing freely in the space with the EEG caps on. For example, mobile EEG studies on Laban movement analysis (LMA) dancing [7] demonstrated the feasibility of classifying specific movements and LABAN effort qualities from distinct EEG signals, and proposed a framework for eliminating motion artifacts from dance analysis. EEG has also proven effective in picking up not only sex-specific effects during contemplation of jazz dancing but also sexindependent effects during physically dancing jazz [8]. It is in this context that we decided to study the brain activity of five experienced dancers while dancing butoh via mobile EEG, recorded simultaneously and synchronously (a process known as hyperscanning). To our knowledge, this study marked the first time that both this type of dance (butoh) and this number of dancers (five) were studied. Moreover, this art-science collaboration allowed us to monitor the creative process through EEG recordings during rehearsals culminating in a theater performance in front of an audience. In this (...truncated)