Short-term plasticity of the primary somatosensory cortex during tool use

Plastic changes within the primary somatosensory cortex (SI) related to tool use are reported. Subjects manipulated a small object with a pair of tongs or with their hand. Functional organization of SI during tool use was compared with that during executing the task with the fingers and during rest, respectively. Topography of SI was assessed using neuromagnetic source imaging based on tactile stimulation of the first (DI) and fifth digit (D5). We found that cortical representations of DI and D5 are further apart during tool use than during non-tool use and rest. Our data suggest that somatosensory cortical maps are part of the neural network representing the modified schema of the hand in which the tool was incorporated.