Combined-modality studies involving TMS can also be used to assess how neural functional connectivity changes during different cognitive tasks and after various interventions. In one recent study combining TMS and EEG, single-pulse TMS was applied to the human FEF while subjects performed either a face discrimination or motion discrimination task (Morishima et al., 2009). Notably, there was a significant difference between the two tasks in the TMS event-related potentials in the right parieto-occipital region. Furthermore, the TMS pulse during the motion task preferentially activated a current source in the region corresponding to area MT (known from fMRI studies to be involved in motion perception), while the fusiform face area was the preferential source of the currents evoked by the TMS pulse during the face task. Taken together, these results suggest that the activity provoked by FEF TMS propagated along different pathways depending on which visual task was being performed, and that the functional connectivity of the FEF varied dynamically as a function of the task parameters.
