Sensory-motor integration and changes in cortical plasticity realized by passive exercise

Sensory-motor integration involves processes in which sensory input is integrated by the central nervous system for the execution of the motor program. Understanding the underlying mechanisms of sensory-motor cortical plasticity has fundamental neurobiological importance and is a requirement for the development of strategies for recovery after brain injury as well as physiological processes such as motor learning. In order to understand the nature of sensory-motor integration and the plastic changes we aimed the development of non-invasive excercise model called "sensory-motor illusion" exercise and to evaluate the validity and effectiveness of this model using Transcranial Magnetic Stimulation (TMS). For this purpose, while the elbow joint movement and biceps muscle length were kept constant during a motor task performed in the biceps muscle, a passive movement was created with a mechanism formed in the metacarpapharyngeal joint of the 2nd finger. In this way, it is aimed to create a transient change in the interconnection of biceps muscle and 1st dorsal interosseous (IDI) muscle cortical sensory-motor representation areas. The targeted change in cortical plasticity was evaluated in 10 healthy individuals before and after exercise by TMS-performed cortical mapping, resting motor threshold (IME), over-threshold stimulation and short latency afferent inhibition (SAI) studies. As a result, it was found that the decrease in biceps muscle IME caused by activation of IDI muscle increased significantly after exercise (p = 0.001). Cortical excitability studies showed that the model developed in this study creates transient plasticity changes in sensory-motor integration. With the validity of the model, new findings that can be used in the treatment processes using adaptive mechanisms for healthy reconstruction of sensory-motor integration in pathological conditions involving stroke, nerve damage, dystonia and maladaptive processes have been obtained.