Measuring the Latency Connectome in the Central Nervous Systems Using Neuroimaging and Neurophysiological Techniques

We will use TMS with paired-pulse technique to activate corticospinal neurons in the primary motor cortex and motorneurons in the brainstem, respectively (Hallett 2007; Ugawa et al. 1991; Ugawa et al.1994). Two stimulations will be separated with various interstimulus intervals to produce collision on nerve fibers with different conduction velocity in the corticospinal tract. The conduction time on nerve fibers in the corticospinal tract with different conduction velocity will be identified and the distribution of these fibers will be calculated.

MRI exams will consist of several sessions including calibration, anatomic, and diffusion MRI scanning (Avram et al. 2013; Avram et al. 2016; Pierpaoli et al. 1996). Data in each exam will be acquired in the left or right forearm (PNS).