Table 1.
Effects of MPTP on distinct populations of M1 cells
| M1 | PTN | CNS | ||
|---|---|---|---|---|
| Number of cells | Pre-MPTP | 325 | 93 | 73 |
| Post-MPTP | 192 | 60 | 53 | |
| Firing rate at rest (spikes/s) | Pre-MPTP | 11.6 ± 9.7 | 18.2 ± 7.5 | 3.0 ± 3.1 |
| Post-MPTP | 9.7 ± 10.9* | 14.2 ± 10.3*** | 3.9 ± 4.6 | |
| Movement-related cells | Pre-MPTP | 263 (81%) | 87 (94%) | 36 (49%) |
| Post-MPTP | 143 (74%) | 55 (92%) | 25 (47%) | |
| Kinematic-encoding cells | Pre-MPTP | 137 (52%) | 51 (59%) | 8 (22%) |
| Post-MPTP | 61 (43%) | 25 (45%) | 5 (20%) | |
| Movement-related residual | Pre-MPTP | 162 | 69 | 9 |
| Post-MPTP | 106 | 45 | 11 | |
| Residual increases | Pre-MPTP | 122 (75%) | 35 (51%) | 9 (100%) |
| Post-MPTP | 73 (69%) | 21 (47%) | 9 (82%) |
Mean values ± SD before and after MPTP treatment were calculated for all M1 cells (left), for PTNs (middle), and for CSNs (right). Movement-related cells = the number of cells (and percentage of total sample) that showed a significant peri-movement modulation in firing. Kinematic-encoding cells = the number of cells (and percentage of movement-related cells) that showed a significant encoding of one or more measure of motor performance. Movement-related residuals = the numbers of cells with significant increases or decreases in residual peri-movement activity (i.e. after regressing out relations to kinematics). Residual increases = the number (and percentage) of cells in which the movement-related residual was an increase in firing. Statistical comparisons are between pre- and post-MPTP populations: *P < 0.05, ***P < 0.001 (Mann-Whitney U-test).