Brain functional changes after a somatosensory discrimination training in healthy young subjects (S28.004)

Objectives: To assess the effect of a somatosensory discrimination training on brain functional activity during tactile stimulation, object manipulation and complex hand-motor functional MRI (fMRI) tasks. Background: Several studies showed that a motor training enhances neuroplasticity in healthy people. Preliminary studies suggested that a somatosensory discrimination training may stimulate the use of cognitive processes, such as movement planning and monitoring, which can be useful during the execution of active motor tasks. Methods: Twenty-six young healthy subjects were randomized into 2 groups to execute a 2-week (W2) training: the experimental group underwent a somatosensory discrimination training consisting of shape, surface and two point distance discrimination; the control group performed a simple object manipulation. At baseline and W2, subjects underwent sensory-motor functional evaluations and fMRI. fMRI tasks were performed with the right hand and consisted of: 1. tactile stimulation; 2. manipulation of a simple object; and 3. a complex active motor task. Results: Right hand dexterity improved in both groups but the improvement was higher in experimental group. After training, the experimental group showed an increased activation of the contralateral post-central gyrus during the tactile stimulation and manipulation tasks. In addition, during complex motor task, the experimental group experienced a reduced recruitment of the ipsilateral pre/post-central gyri and an increased activation of the contralateral striatum and pallidum. At W2, control group showed an increased recruitment of the contralateral cerebellum during the active motor task. Conclusions: These findings suggest that a somatosensory discrimination training of the right hand can facilitate the recruitment of the contralateral primary sensory cortex during tactile stimulation and object manipulation tasks. Furthermore, it determines the use of different brain activation strategies during hand movement. This study suggests that a passive somatosensory discrimination training could be useful for lesion-specific rehabilitation following, e.g., stroke.