Table 2.
Different patterns of neuronal activity in the GPi.
| Pattern of neuronal activity | Number of cells | Frequency (Hz) | ISI (ms) | CV of ISI |
|---|---|---|---|---|
| Grouped discharge | 7 | 31 ± 12 (18–51) | 35 ± 50 (2–1309) | 1.6 ± 0.5 (1.0–2.1) |
| Low frequency | 12 | 18 ± 6 (9–29) | 52 ± 51 (25–366) | 0.7 ± 0.2 (0.2–1.4) |
| Tonic | 20 | 60 ± 38 (37–176) | 19 ± 8 (3–79)△ | 0.4 ± 0.1 (0.4–0.5)△ |
| Irregular | 22 | 63 ± 15 (40–93) | 19 ± 20 (11–229)△ | 0.8 ± 0.3 (0.7–1.2)△ |
| Tremor-related | 19 | 82 ± 42 (30–135) | 11 ± 14 (12–117) | 1.2 ± 0.4 (0.7–1.7) |
△ Indicates significance (Bonferroni test, p < 0.05). Neurons with tonic firing were compared with neurons with low frequency firing. Neurons with irregular discharge were compared with neurons with grouped discharge. Values in brackets represent ranges. GPi, globus pallidus internus; ISI, interspike interval; CV, coefficient of variation.