Table 1.
Motoneurone passive and threshold properties
| Weight-bearing | Unweighted | ||||
|---|---|---|---|---|---|
| Property | Fast | Slow | Fast | Slow | Difference |
| Rheobase (nA) | 8.0 ± 4.7 (88) | 6.0 ± 3.8 (60) | 10.6 ± 4.3 (52) | 6.4 ± 4.2 (23) | B |
| Input resistance (MΩ) | 1.7 ± 1.5 (55) | 2.7 ± 1.4 (51) | 1.7 ± 1.3 (45) | 2.6 ± 1.3 (20) | A |
| Spike amplitude (mV) | 77 ± 12.3 (91) | 84 ± 12.1 (58) | 73 ± 12.0 (51) | 74 ± 11.5 (24) | B |
| Rheobasic spike amplitude (mV) | 58 ± 7.5 (89) | 64 ± 7.7 (60) | 52 ± 7.8 (51) | 55 ± 7.2 (19) | B |
| RMP (mV) | −61 ± 7.4 (87) | −63 ± 7.5 (57) | −59 ± 7.5 (48) | −63 ± 7.7 (24) | |
| AHP half-decay time (ms) | 14.4 ± 3.8 (93) | 28.6 ± 3.9 (61) | 14.6 ± 4.3 (52) | 27.0 ± 3.8 (24) | A |
| AHP amplitude (mV) | 1.5 ± 0.9 (80) | 2.9 ± 0.7 (57) | 1.3 ± 0.7 (52) | 2.0 ± 1.0 (24) | B |
| Spike threshold (mV) | −43 ± 9.1 (83) | −42 ± 8.8 (55) | −38 ± 9.3 (46) | −45 ± 8.9 (19) | C |
| Time constant (ms) | 4.5 ± 1.3 (53) | 5.4 ± 1.9 (46) | 4.0 ± 0.9 (47) | 4.4 ± 0.9 (22) | B |
| Cell capacitance (nF) | 3.5 ± 1.8 (30) | 2.8 ± 1.8(34) | 2.8 ± 1.5 (38) | 2.1 ± 1.2 (20) | B |
Data are presented as means ± 1 s.d. Two-way ANOVA was used for analysis. In right-hand column, A indicates type (slow versus fast) of significant main effect only (P < 0.01) and B indicates both group (weight-bearing versus unweighted) and type (fast versus slow) significant main effects (P < 0.02), with difference due to group effect shown in bold, and C indicates a significant interaction effect (P < 0.02), with mean which is different from all others shown in bold.