TOPOGRAPHIC MAPPING OF TRANSCRANIAL MAGNETIC STIMULATION DATA ON SURFACE RENDERED MR-IMAGES OF THE BRAIN

We present a method for the coregistration and topographic mapping of trans-cranial magnetic stimulation (TCMS) data on surface rendered ima ges of the cortex, derived from Magnetic Resonance Images (MRI). We de scribe the TCMS procedure and the methods used to locate the TCM stimu lation sites in the MRI coordinate system, and the algorithms needed t o depict the TCMS distribution as a pseudocolour contour map on the co rtical surface. The methods are Validated using TCMS data from the han d (thenar) and leg (tibialis muscle). The methods used correctly depic t the expected motor representations of each of these areas and we the refore propose that this technique may be used as a functional imaging tool in the investigation of cortical function in both normals and pa tients. (C) 1997 Elsevier Science Ireland Ltd.