Autonomic modulations to cardiac dynamics in response to affective touch: Differences between social touch and self-touch

Abstract

The autonomic nervous system plays a vital role in self-regulation and responding to environmental demands. Autonomic dynamics have been hypothesized to be involved in perceptual awareness and the physiological implementation of the first-person perspective. Based on this idea, we hypothesized that the autonomic activity measured from cardiac dynamics could differentiate between social touch and self-touch. In our study, we used a newly developed method to analyze the temporal dynamics of cardiac sympathetic and parasympathetic activities during an ecologically valid affective touch experiment. We revealed that different types of touch conditions—social-touch, self-touch, and a control object-touch—resulted in a decrease in sympathetic activity. This decrease was more pronounced during social touch, as compared to the other conditions. Following sympathetic decrease, we quantified an increase in parasympathetic activity specifically during social touch, further distinguishing it from self-touch. Importantly, by combining the sympathetic and parasympathetic indices, we successfully differentiated social touch from the other experimental conditions, indicating that social touch exhibited the most substantial changes in cardiac autonomic indices. These findings may have important clinical implications as they provide insights into the neurophysiology of touch, relevant for aberrant affective touch processing in specific psychiatric disorders and for the comprehension of nociceptive touch.

Linking heartbeats with the cortical network dynamics involved in self-social touch distinction

“…The role of parasympathetic/vagal activity remains poorly understood, although many contexts revealed that affective touch activates the parasympathetic nervous system [50][51][52][53][54] . In our recent research, we showed that affective touch causes a decrease in cardiac sympathetic activity and an increase in cardiac parasympathetic activity, which was more pronounced in the case of social touch 29 .…”

“…The protocol consisted in the recording of EEG and ECG data while undergoing three distinct conditions: social touch (being stroked on the forearm by the experimenter), self-touch (stroking of the participant's own forearm), and object-touch (participant stroking a pillow) as a control condition. Each of the three conditions lasted 180 seconds, that were analyzed in the segments 0-60, 60-120 and 120-180 seconds, as done previously 29 .…”

“…Therefore, in this study we aimed at identifying the brain dynamics that are specific to affective touch, expanding on our previous findings 29 .…”

“…Furthermore, disruptions in the autonomic system that may affect temperature perception or pain sensitivity do not necessarily impact affective touch 31 , demonstrating the specificity of the pathways involved in this type of tactile experience. Therefore, in this study we aimed at identifying the brain dynamics that are specific to affective touch, expanding on our previous findings 29 .…”

Measuring the time-dependent effects of dobutamine on the modulations of cardiac activity in rats

“…Dobutamine acts as a positive ionotropic, known as sympathomimetic [2]. In our proposed method, previously validated in humans [10,27], we accurately show the time-dependent effects of autonomic elicitation induced by dobutamine in rats, unraveling some of the key components of cardiac regulation by both sympathetic and parasympathetic systems. As expected, our results show that dobutamine triggers an increase in sympathetic activity, shown as a sudden increase in slow fluctuations in HRV, followed by a transient increase in the baseline heart rate.…”