Changes of brain connectivity in social interaction tasks

Social interactions rely upon mutual information exchange where our own behaviour changes in response to another while at the same time our own actions also modify theirs. Previous research has demonstrated specific and differential modulations of alpha ERD/S pre-dominantly at centro-parietal locations in various modes of dual task finger movement coordination [1, 2]. Employment of visual resources is considered essential for phase-locking of movement profiles and hence subsequent coordination [3]. Similarly, decision making can become important in relation with motor act for sustained and successful performance of goal directed activity [4]. Based on these considerations and previous research [1, 2], connectivity of motor/ sensory motor cortex with occipital and frontal cortex is expected and explored in this preliminary investigation.Subjects in pair performed a finger movement task under three conditions: intrinsic- ignore; in-phase - follow; and anti-phase - oppose their partner’s movement patterns. Correlation changes (active against a baseline data) of centro-parietal (Cp3, Cpz and Cp4) versus all the electrodes (60) were estimated for each task. Bi-directional filters (in the range 8-10/10-12 Hz) were applied to explore effects on amplitude and phase in lower/upper mu bands. Topographic maps depicted task modulated correlation changes in the 8-10 Hz range. The results depicted strong associations between visual and frontal cortex (+ve and -ve correlation changes respectively) with the centro-parietal region in the case of Anti-phase. In the Intrinsic context strong correlation with frontal region was noted. No associations were found in the In-phase task. These results were statistically confirmed (ANOVA repeated measures).The +ve association with posterior regions in the Anti-phase condition implicates visuo-spatial discrimination [2] as essential in this context. However, -ve relation with frontal region is intriguing and requires further investigation. Strong +ve correlation with frontal region in the Intrinsic task may reflect aspects of inhibitory control [1] to avoid synchronisation with the partner. Lack of regional association in the In-phase task confirms previous finding that it reflects a natural state of coordination requiring little decision making or visual attentional resources.References[1] M. Naeem, G. Parasad, D. Watson and J.A.S. Kelso Electrophysiological Signatures of Intentional Social Coordination in the 10-12 Hz Range (NeuroImage 59 (2012) 1795–1803 doi:10.1016/j.neuroimage.2011.08.010) [2] M. Naeem, G. Parasad, D. Watson and J.A.S. Kelso Functional dissociation of brain rhythms in social coordination(Accepted -Clinical Neurophysiology(2012)- doi:10.1016/j.clinph.2012.02.065[3] Tognoli E, Lagarde J, de Guzman GC, Kelso JAS. The phi complex as a neuromarker of human social coordination. Proc.Natl.Acad.Sci.USA. 2007a; 104:8190-8195.[4] Georgopoulos AP. Neural aspects of cognitive motor control. Curr.Opin.Neurobiol. 2000;10: 238-241.