Imaging the brain before, during, and after transcranial magnetic stimulation.

This article provides a brief overview of current trends in combining neuroimaging and transcranial magnetic stimulation (TMS). First, I outline the utility of magnetic-resonance imaging (MRI) and frameless stereotaxy for planning, monitoring and documenting the location of the TMS coil relative to the subject's brain. Second, I describe two novel methods, based on the combination of TMS with positron emission tomography (PET) or with electroencephalography (EEG), for the assessment of connectivity and excitability of the human cerebral cortex. Finally, I point out the utility of PET and MRI for evaluating possible long-term effects of repetitive TMS.