TY - JOUR
T1 - Motoneuron intrinsic properties, but not their receptive fields, recover in chronic spinal injury
AU - Johnson, Michael D.
AU - Kajtaz, Elma
AU - Cain, Charlette M.
AU - Heckman, C. J.
PY - 2013
Y1 - 2013
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 MRRFsundergo a recovery that parallels that of the PIC. Using the chronic spinal cat in acute terminal decerebrate preparations,wefound 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.
AB - 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 MRRFsundergo a recovery that parallels that of the PIC. Using the chronic spinal cat in acute terminal decerebrate preparations,wefound 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.
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U2 - 10.1523/JNEUROSCI.2609-13.2013
DO - 10.1523/JNEUROSCI.2609-13.2013
M3 - Article
C2 - 24285887
AN - SCOPUS:84888247754
VL - 33
SP - 18806
EP - 18813
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 48
ER -