Testing Tactile Masking between the Forearms

Abstract

Masking, in which one stimulus affects the detection of another, is a classic technique that has been used in visual, auditory, and tactile research, usually using stimuli that are close together to reveal local interactions. Masking effects have also been demonstrated in which a tactile stimulus alters the perception of a touch at a distant location. Such effects can provide insight into how components of the body's representations in the brain may be linked. Occasional reports have indicated that touches on one hand or forearm can affect tactile sensitivity at corresponding contralateral locations. To explore the matching of corresponding points across the body, we can measure the spatial tuning and effect of posture on contralateral masking. Careful controls are required to rule out direct effects of the remote stimulus, for example by mechanical transmission, and also attention effects in which thresholds may be altered by the participant's attention being drawn away from the stimulus of interest. The use of this technique is beneficial as a behavioural measure for exploring which parts of the body are functionally connected and whether the two sides of the body interact in a somatotopic representation. This manuscript describes a behavioural protocol that can be used for studying contralateral tactile masking. Video LinkThe video component of this article can be found at

Cortical interaction of bilateral inputs is similar for noxious and innocuous stimuli but leads to different perceptual effects

“…Sensory integration of concurrent stimuli has been explored for visual [7][8][9][10], auditory [11,12], tactile [9,[13][14][15][16] and vibrotactile [17][18][19][20][21] modalities. For example, integration of different vibration signals from distinct locations leads to assimilation or averaging effects, indicating that tactile perception can be global although information arises from different sensory channels [20].…”