期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：2
页码：619-624
DOI：10.1073/pnas.1419539112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceWhen we actively explore objects by touch, the brain receives two types of signals, tactile sensory inputs and signals about the exploratory movement, which must be combined to perceive the shape and location of objects in space. Whereas these signals usually come from the same body part, we have developed a technique to separate them, directing the tactile signals to one hand and the movement signals to the other. We find that separated and synchronized signals are combined as if they arose from the same hand. Our results suggest that to solve the difficult problem of multidimensional signal combination in touch perception, the brain uses a simplified, source-independent representation of movement. Although motor actions can profoundly affect the perceptual interpretation of sensory inputs, it is not known whether the combination of sensory and movement signals occurs only for sensory surfaces undergoing movement or whether it is a more general phenomenon. In the haptic modality, the independent movement of multiple sensory surfaces poses a challenge to the nervous system when combining the tactile and kinesthetic signals into a coherent percept. When exploring a stationary object, the tactile and kinesthetic signals come from the same hand. Here we probe the internal structure of haptic combination by directing the two signal streams to separate hands: one hand moves but receives no tactile stimulation, while the other hand feels the consequences of the first hand's movement but remains still. We find that both discrete and continuous tactile and kinesthetic signals are combined as if they came from the same hand. This combination proceeds by direct coupling or transfer of the kinesthetic signal from the moving to the feeling hand, rather than assuming the displacement of a mediating object. The combination of signals is due to perception rather than inference, because a small temporal offset between the signals significantly degrades performance. These results suggest that the brain simplifies the complex coordinate transformation task of remapping sensory inputs to take into account the movements of multiple body parts in haptic perception, and they show that the effects of action are not limited to moving sensors.
