Physiological properties of incipient myelinated cutaneous HTMRs in neonatal mice
| HTMRs (Postnatal age, 4.2 ± 1.6 d) | LTMRs* (Postnatal age, 4.2 ± 1.6 d) | |||||
|---|---|---|---|---|---|---|
| All | Lamina I/IIo | Lamina I–V | All | RA | SA | |
| Mechanical threshold (mN) | 2.1 ± 2.0 (27) | 3.2 ± 2.6 (9) | 1.5 ± 1.4 (18) | 0.5 ± 1.2 (26) | 0.6 ± 1.3 (19) | 0.2 ± 0.4 (7) |
| median | 2.45 | 2.45 | 0.87 | 0.07 | 0.07 | 0.07 |
| Spike half-width (msec) | 2.1 ± 0.7 (26) | 2.6 ± 0.7 (8) | 1.9 ± 0.5 (18) | 0.8 ± 0.1 (18) | 0.8 ± 0.1 (12) | 0.8 ± 0.1 (6) |
| median | 2.15 | 2.45 | 1.75 | 0.80 | 0.90 | 0.80 |
| Spike amplitude (mV) | 70.7 ± 12.3 (26) | 69.5 ± 15.6 (8) | 70.7 ± 11.1 (18) | 52.4 ± 12.5 (18) | 55.8 ± 11.6 (12) | 45.6 ± 12.4 (6) |
| median | 70.38 | 70.50 | 70.25 | 54.25 | 57.06 | 51.63 |
| AHP half-width (msec) | 8.0 ± 4.0 (23) | 9.7 ± 2.8 (5) | 7.5 ± 4.2 (18) | 3.3 ± 1.1 (16) | 3.7 ± 1.0 (12) | 2.1 ± 0.4 (4) |
| median | 7.00 | 9.30 | 6.40 | 3.35 | 3.80 | 2.15 |
| Conduction velocity (m/sec) | 0.6 ± 0.1 (28) | 0.6 ± 0.1 (10) | 0.6 ± 0.1 (18) | 0.8 ± 0.2 (32) | 0.8 ± 0.2 (23) | 0.8 ± 0.2 (9) |
| median | 0.57 | 0.53 | 0.61 | 0.73 | 0.71 | 0.81 |
Values presented are mean ± SD. Numbers of afferents included in each measurement are provided in parentheses.
↵* LTMR data are from afferents in Woodbury et al. (2001) and our unpublished observations.