Arslanova I, Gomi H, Haggard P

When an object moves across the skin, cutaneous signals from multiple contact points (e.g., multiple fingers) need to be encoded to represent its spatial direction and coordinate subsequent movements. Yet, the mechanisms for combining tactile inputs from multiple fingers remain elusive. Here, we studied integration of tactile motion information, by asking participants to report the average direction of two motion trajectories delivered simultaneously to two fingers. The stimulated fingers were either within a single hemisphere (index/middle finger of the right hand) or between different hemispheres (index finger on right and left hand). Our result showed that when participants had to combine motion information within the same hand, their performance showed significant loss of precision. Surprisingly, when the exact same stimuli were delivered to fingers in different hemispheres, precision and error rates for combined estimates were significantly higher. This finding suggests a more efficient integration of spatiotemporal information when it’s presented interhemispherically rather than within one hemisphere.