Tactile facilitation during actual and mere expectation of object reception

Abstract

During reaching and grasping movements tactile processing is typically suppressed. However, during a reception or catching task, the object can still be acquired but without suppressive processes related to movement execution. Rather, tactile information may be facilitated as the object approaches in anticipation of object contact and the utilization of tactile feedback. Therefore, the current study investigated tactile processing during a reception task. Participants sat with their upper limb still as an object travelled to and contacted their fingers. At different points along the object’s trajectory and prior to contact, participants were asked to detect tactile stimuli delivered to their index finger. To understand if the expectation of object contact contributed to any modulation in tactile processing, the object stopped prematurely on 20% of trials. Compared to a pre-object movement baseline, relative perceptual thresholds were decreased throughout the object’s trajectory, and even when the object stopped prematurely. Further, there was no evidence for modulation when the stimulus was presented shortly before object contact. The former results suggest that tactile processing is facilitated as an object approaches an individual’s hand. As well, we purport that the expectation of tactile feedback drives this modulation. Finally, the latter results suggest that peripheral masking may have reduced/abolished any facilitation.

How visuomotor predictability and task demands affect tactile sensitivity on a moving limb during object interaction in a virtual environment

“…However, once the hand starts moving, any visual memory should be eliminated, or substantially reduced. If the vibration, or other tactile information, was informative to the movement task, participants might have detected more vibrations as task difficulty increased, similar to Voudouris & Fiehler [ 5 ] where task-relevant vibrations were enhanced and task-irrelevant ones were suppressed [ 5 ] or similar to Manzone, Tremblay and Chua [ 59 ] who found that the expectation of intercepting a real world object led to lower detection thresholds [ 59 ].…”