抄録
Proprioceptive sensory feedback provided by a motion assist device may facilitate neuronal plasticity which is known to play an important role in learning and rehabilitation. We investigated effects of sensory feedback timing on learning a sensory-motor association task. Rats were trained to respond to an air-puff stimulus on a forepaw by releasing the lever pressed with the stimulated forepaw (compatible condition) or with the non-stimulated forepaw (incompatible condition), i.e., a choice reaction time task. When the success rate exceeded 85%, the compatibility condition was changed (i.e., reversal learning). During training, an error trial was followed by a lever-activation trial where the correct lever (on which the forepaw was placed) was elevated automatically (which mimicked a correct lever-release response) at 120, 220, 320, or 420 ms after air-puff stimulation in four groups of rats. Such lever activation did not occur when the rat made a lever-release response before these preset timings. The control group received no lever-activation. Results indicate that learning speed was reduced significantly in the group that received lever-activation at 220 ms after air-puff stimulation. The finding suggests that the timing of movement-signal application is important in learning and thus should be considered in developing more efficient assist or rehabilitation devices.
