by Hila Gvirts
In this Video from the Joint improvisation meeting 2015 in Paris at the CNRS site Pouchet I presented the project I developed during “Störung/Hafraah” at minute 4:
My post-doc thesis in neuroscience at Haifa university under the supervision of Prof. Simone Shamay-Tsoory is inspired by the “Störung/Hafraah” project. I am interested in examining the unison phenomenon and the feeling of togetherness that is triggered by synchronized movement. In the scope of the project, Shuli Enosh (a dancer from Yasmine Godder Company) and I conducted a pilot study (a short workshop) to examine the emotional effects of synchrony for people with Parkinson’s. This was done during the second “Open House” for the “Störung/Hafraah” project and the results were presented in Freiburg. As a neuroscientist, I am interested in understanding what brain mechanisms underlie the ability to synchronize with another person.
The inferior frontal gyrus (IFG) is one of the core regions associated with several behaviors that subserve synchrony. The IFG has been shown to play a major role in mimicry (Wang, Ramsey, & Hamilton, 2011), imitation (Goldenberg & Karnath, 2006) and emotional empathy (Shamay-Tsoory et al., 2009). Interestingly, it has been suggested that this region is part of the mirror neuron system (Iacoboni & Dapretto, 2006). Recently, Enticott et al., (2012) showed that stimulation to this region significantly reduced the activation of an individual’s motor system during the observation of another’s behaviour (while no effect of stimulation for inferior parietal lobule). The left IFG has been discussed in relation to the matching of motor plans (Iacoboni et al., 1999; Rizzolatti, Fogassi, & Gallese, 2001) through the encoding and representation of goals and intentions from observed actions (Cattaneo, Caruana, Jezzini, & Rizzolatti, 2009; Gallese & Sinigaglia,2011; Rizzolatti & Sinigaglia, 2010).
Collectively, these findings may indicate that disruption of this motor resonance system would lead to disrupted ability to synchronize. In the proposed study, we plan to examine the role of the left IFG in synchrony using direct current stimulation (tDCS). tDCS is a non-invasive brain stimulation technique that involves the application of mild electrical stimulation to the scalp in order to modulate cortical excitability. Typically, anodal stimulation is associated with an increase in cortical excitability, while cathodal stimulation yields a decrease in excitability(Stagg & Nitsche, 2011). Using two paradigms developed in collaboration with Matan Karklinsky (also in “Störung/Hafraah”) we plan to test the effect of cathodal and anodal stimulation targeting the left IFG on interpersonal synchrony.
The tool developed by Matan in collaboration with Tom Yuval is a computerized two-dimensional synchrony game. The objective of this game is to measure real time synchrony among interacting humans. We just finished a pilot study for validation of this tool. Results indicate that the tool distinguishes well between synchronized movement and unsynchronized (e.g. two people that were instructed to move together vs. two people that were instructed to freely move in the same space). Interestingly, even when participants were instructed to move freely, in some cases some level of synchrony is observed . Further investigation revealed that the tendency to synchronize under free movement condition is associated with friendly relations between the two players, suggesting that the level of synchronization reflects the level of intimacy. A collaboration with a another scientist from the project, Anat Dahan, yielded an additional paradigm for studying synchrony, which we are currently developing. This paradigm will allow us to measure synchrony while dancing: between two subjects dancing together, between a subject and an avatar and between a subject and several avatars (the latter will allow us to examine herding behavior).
photo: Levin Sottru