|Percentage of Dependent Variable Variance Accounted for by Independent Variable(s)|
|Test Design||Independent Variables That Account for Variance in Dependent Variable||Rheobase||Depolarization Threshold||Recruitment Current||Derecruitment Current|
|Motoneuron and RMP (common)||21.4||10.3||19.8||18.3|
|l/Input resistance (unique)||21.0***||0.0||34.9***||34.8***|
|Motoneuron, RMP, and l/Input resistance (common)||40.5||11.7||33.2||33.6|
Regressions of rheobase (current threshold for action potential initiation during 40-ms depolarizing pulse), depolarization threshold (voltage excursion from resting potential to reach the action potential threshold), and input resistance on motoneuron identity [Motoneuron; EUS (present study) vs. hindlimb (>Carp et al. 2008 and unpublished data], resting membrane potential (RMP), and/or the inverse of input resistance determine the variance in the dependent variables, accounted for by the independent variables. For multiple regressions (i.e., two- and three-factor designs), the percentage of variance in the dependent variable accounted for is shown for the entire model (All), for the unique contribution of each independent variable individually (Motoneuron, RMP, or 1/Input resistance only), and for the covariation among independent variable contributions (Common; calculated as the difference between the variance accounted for by the entire model and the sum of the unique contributions of the independent variables individually).
↵* P < 0.05,
↵** P < 0.01, and
↵*** P < 0.001, variance accounted for by variable(s) significantly different from zero.