EEG captures affective touch: CT-optimal touch and neural oscillations

Abstract

Tactile interactions are of developmental importance to social and emotional interactions across species. In beginning to understand the affective component of tactile stimulation, research has begun to elucidate the neural mechanisms that underscore slow, affective touch. Here, we extended this emerging body of work and examined whether affective touch (C tactile [CT]-optimal speed), as compared to nonaffective touch (non-CT-optimal speed) and no touch conditions, modulated EEG oscillations. We report an attenuation in alpha and beta activity to affective and nonaffective touch relative to the no touch condition. Further, we found an attenuation in theta activity specific to the affective, as compared to the nonaffective touch and no touch conditions. Similar to theta, we also observed an attenuation of beta oscillations during the affective touch condition, although only in parietal scalp sites. Decreased activity in theta and parietal-beta ranges may reflect attentional-emotional regulatory mechanisms; however, future work is needed to provide insight into the potential neural coupling between theta and beta and their specific role in encoding slow, tactile stimulation.