Tactile suppression stems from sensation-specific sensorimotor predictions

Abstract

The ability to sample sensory information with our hands is crucial for smooth and efficient interactions with the world. Despite this important role of touch, tactile sensations on a moving hand are perceived weaker than when presented on the same but stationary hand.1-3 This phenomenon of tactile suppression has been explained by predictive mechanisms, such as forward models, that estimate future sensory states of the body on the basis of the motor command and suppress the associated predicted sensory feedback.4 The origins of tactile suppression have sparked a lot of debate, with contemporary accounts claiming that suppression is independent of predictive mechanisms and is instead akin to unspecific gating.5 Here, we target this debate and provide evidence for sensation-specific tactile suppression due to sensorimotor predictions. Participants stroked with their finger over textured surfaces that caused predictable vibrotactile feedback signals on that finger. Shortly before touching the texture, we applied external vibrotactile probes on the moving finger that either matched or mismatched the frequency generated by the stroking movement. We found stronger suppression of the probes that matched the predicted sensory feedback. These results show that tactile suppression is not limited to unspecific gating but is specifically tuned to the predicted sensory states of a movement.

Linking Signal Relevancy and Intensity in Predictive Tactile Suppression

“…The increase in suppression for tactile compared to visual feedback points to a predictive component based on the expected tactile feedback at the end of the reach. Together with other studies ( Fraser and Fiehler, 2018 ; Gertz et al, 2018 ; Manzone et al, 2018 ; Führer et al, 2021 ; Voudouris and Fiehler, 2021 ), our results support the assumption that suppression of external tactile probing stimuli cannot be explained by unspecific gating alone but is adjusted to predicted somatosensory consequences of the movement.…”

“…A total of 68 students participated in the study and completed the experiment. The sample size was not calculated a priori , but was chosen to be comparable to previous studies of tactile suppression (e.g., Fraser and Fiehler, 2018 ; Gertz et al, 2018 ; Manzone et al, 2018 ; Voudouris et al, 2019 ; Führer et al, 2021 ). In exchange for their participation, participants received either course credit, or financial compensation at the rate of eight Euro/hour.…”

“…Externally generated stimuli are also harder to detect during movement, compared to a resting state (Chapman et al, 1987;Fraser and Fiehler, 2018;Gertz et al, 2018;Manzone et al, 2018;Voudouris and Fiehler, 2021). Importantly, this relative suppression is stronger for predicted compared to unpredicted somatosensory consequences of movement (Voudouris et al, 2019;Führer et al, 2021). In sum, tactile suppression provides a well-established behavioral measure of the strength of somatosensory predictions and allows us to understand how the brain utilizes predictions of future sensory states to efficiently process signals resulting from goaldirected movements.…”