In a particularly intriguing recent study, Grefkes et al (2010) utilized fMRI and functional connectivity analysis techniques to explore the network changes produced by rTMS of the contralesional hemisphere in stroke patients. This study was motivated by previous work that demonstrated significant disturbances in the effective connectivity between different cortical regions in stroke patients: reduced coupling between ipsilesional SMA and M1, reduced coupling between the bilateral SMAs, and increased interhemispheric inhibition from contralesional M1 to ipsilesional M1 during movements with the paretic hand (Grefkes et al., 2008). Interestingly, the weaker the coupling between ipsilesional SMA and M1, and the greater the interhemispheric inhibition from contralesional M1 to ipsilesional M1, the worse the performance was in the paretic hand. After 1Hz rTMS to the contralesional cortex, motor performance of the paretic hand improved. rTMS was also associated with an increase in the endogenous coupling of ipsilesional SMA and M1, and with a significant decrease of the pathologic inhibition from contralesional M1 to ipsilesional M1 with movement of the paretic hand. The magnitude of the reduction in this pathologic inhibition was correlated
