Technique of Topographical mapping of FDI muscle response after Single pulse TMS stimulation: A method to study inter hemispheric symmetry and plasticity of human motor cortex

The aim of this study was to investigate the technique of Topographical mapping of first dorsal interosseous (FDI) muscle response after Single pulse Trans cranial Magnetic stimulation (TMS), in a single normal subject, to study inter hemispheric symmetry of plasticity of motor cortex. TMS induced motor evoked potential (MEP) over an area of motor cortex was mapped in two dimensional space using pseudo colour. This is a simple technique which gives a qualitative as well as quantitative idea of brain excitability. Using this technique, a map of MEP of FDI for a normal individual was created followed by mapping of same individual after continuous theta bust stimulation (cTBS) and intermittent theta bust stimulation (iTBS), to induce plasticity of motor cortex. The scope of this technique to examine inter hemispheric symmetry of plasticity of motor cortex of human brain is discussed.