TY - JOUR T1 - Motoneuron Intrinsic Properties, but Not Their Receptive Fields, Recover in Chronic Spinal Injury JF - The Journal of Neuroscience JO - J. Neurosci. SP - 18806 LP - 18813 DO - 10.1523/JNEUROSCI.2609-13.2013 VL - 33 IS - 48 AU - Michael D. Johnson AU - Elma Kajtaz AU - Charlette M. Cain AU - C.J. Heckman Y1 - 2013/11/27 UR - http://www.jneurosci.org/content/33/48/18806.abstract N2 - Proper movement execution relies on precise input processing by spinal motoneurons (MNs). Spinal MNs are activated by limb joint rotations. Typically, their movement-related receptive fields (MRRFs) are sharply focused and joint-specific. After acute spinal transection MRRFs become wide, but their manifestation is not apparent, as intrinsic excitability, primarily resulting from the loss of persistent inward currents (PICs), dramatically decreases. PICs undergo a remarkable recovery with time after injury. Here we investigate whether MRRFs undergo a recovery that parallels that of the PIC. Using the chronic spinal cat in acute terminal decerebrate preparations, we found that MRRFs remain expanded 1 month after spinal transaction, whereas PICs recovered to >80% of their preinjury amplitudes. These recovered PICs substantially amplified the expanded inputs underlying the MRRFs. As a result, we show that single joint rotations lead to the activation of muscles across the entire limb. These results provide a potential mechanism for the propagation of spasms throughout the limb. ER -