Spinal cord injury (SCI) causes paralysis but also induces severe alterations to reflex function, resulting in debilitating involuntary muscle contractions or spasms. Our hypothesis is that the mechanisms underlying these reflex alterations are not identical across people with SCI but vary systematically with both the severity and location of injury. As a consequence, we suggest that treatment for spasms must be specifically tailored to individuals, depending on the nature of their injury. Our overall goal is to establish the rationale for such patient specific therapies, helping to transform clinical treatment of spasms and improve functional outcomes following SCI. This proposal uses a range of unique mouse preparations and novel therapeutics to test how these cellular alterations underlie the variability seen in spasms post SCI and provide directions for therapeutic intervention.