Table 1.
Comparison of synaptic actions from the contralateral RN, contralateral PT and ipsilateral MLF in spinal border neurones and in lumbar motoneurones
| SB neurones present study | VSCT and SB neurones* | α motoneurones** | |||
|---|---|---|---|---|---|
| co RN n = 42 | co PT n = 38 | i MLF n = 42 | co RN n = 82 | co RN n = 12 | |
| Proportions of neurones with: | |||||
| Monosynaptic EPSPs | 17% | 49% | 17% | ||
| Disynaptic EPSPs | 43% | 39% | 49% | 19% | 53% |
| Mono and/or disynaptic EPSPs | 57% | 83% | |||
| Disynaptic IPSPs | 81% | 55% | 54% | 41% | 42% |
| Mean latencies (ms) of: | |||||
| Monosynaptic EPSPs (0.5–0.9 ms segmental) | 4.33 ± 0.11 | 3.28 ± 0.05 | |||
| Disynaptic EPSPs (1.1–1.4 ms segmental) | 4.66 ± 0.20 | 5.86 ± 0.76 (trisyn) | 4.02 ± 0.15 | 4.79 ± 0.09 | |
| Disynaptic IPSPs (1.1–2.2 ms segmental) | 5.16 ± 0.06 | 5.95 ± 0.24 (trisyn) | 4.24 ± 0.11 | 5.17 ± 0.18 | |
*
Data from Fig. 1 in Baldissera & ten Bruggencate, 1976.
**
Data from Fig. 7 in Stecina et al. 2008.
Note that latencies of disynaptic EPSPs from RN were 1.2 ms shorter than of most likely trisynaptic EPSPs from co PT. The difference between latencies of disynaptic IPSPs from RN and from PT was smaller (0.79 ms) but it was also compatible with a more direct coupling. Note also similar latencies of disynaptic EPSPs and IPSPs of RN origin in SB neurones and in hindlimb alpha-motoneurones.