Current pediatric studies have employed non-invasive brain stimulation, and most commonly use the single or paired-pulses of Transcranial Magnetic Stimulation (TMS) to evaluate brain plasticity by assessing cortical excitability. To date, there is only one infant study using TMS to assess cortical excitability with perinatal stroke. As a unique aspect of investigation, this study will combine Magnetic Resonance Imaging (MRI)/ Diffusion Tensor Imaging (DTI) and TMS to provide an additional opportunity to assess both the cortical excitability and corticospinal tract (CST) integrity in infants with perinatal stroke.