Electrophysiological passive and active properties of medium spiny neurons in the core and shell of nucleus accumbens of naive and rewarded animals
| Naive | Statistics | Rewarded | Statistics | |||
|---|---|---|---|---|---|---|
| Core | Shell | t/F, p | Core | Shell | t/F, p | |
| Passive membrane properties | ||||||
| Resting membrane potential, mV | −81.5 ± 0.8 (31) | −80.0 ± 0.8 (20) | 0.48, 0.86 | −81.2 ± 0.6 (47) | −79.7 ± 0.8 (31) | 1.60, 0.21 |
| Cell capacitance, pF | 136 ± 7 (31) | 84 ± 4 (20) | 5.66, <0.0001 | 130 ± 5 (47) | 88 ± 5 (31) | 5.79, <0.0001 |
| Input resistance, MΩ | 67 ± 7 (31) | 99 ± 8 (20) | 3.07, 0.0053 | 74 ± 5 (47) | 118 ± 7 (31) | 5.23, <0.0001 |
| Active membrane properties | ||||||
| V/I curve (−500 to 0 pA) | −12.0 ± 0.3 (15) | −17.2 ± 0.4 (11) | 55.8, 3.61−13 | −12.7 ± 0.2 (33) | −17.7 ± 0.3 (21) | 227, 8.66–47 |
| V/I curve (0 to +100 pA) | 5.4 ± 0.5 (15) | 10.8 ± 0.6 (11) | 40.4, 4.11−9 | 6.1 ± 0.3 (33) | 9.8 ± 0.4 (21) | 47.3, 4.65−11 |
| Sag ratio at −500 pA, mV | 1.028 ± 0.003 (15) | 1.053 ± 0.005 (11) | 4.32, <0.0001 | 1.029 ± 0.002 (33) | 1.053 ± 0.004 (21) | 5.85, <0.0001 |
| Number of spikes, AP# | 3.2 ± 0.2 (31) | 6.7 ± 0.3 (20) | 72.8, 8.57−17 | 4.5 ± 0.2 (47) | 6.8 ± 0.2 (31) | 66.6, 8.93−16 |
| Firing frequency, Hz | 8.1 ± 0.4 (31) | 14.5 ± 0.6 (20) | 81.7, 1.48−18 | 9.6 ± 0.4 (47) | 14.9 ± 0.4 (31) | 84.1, 2.25−19 |
| Current to threshold, pA | 966 ± 58 (29) | 737 ± 45 (20) | 2.73, 0.014 | 943 ± 52 (43) | 643 ± 36 (29) | 4.32, <0.0001 |
| AP threshold, mV (*) | −44 ± 1.5 (29) | −39.5 ± 1 (20) | 2.37, 0.038 | −44 ± 1 (43) | −39 ± 1 (29) | 2.85, 0.010 |
| Δ RMP/AP threshold, mV (Δb) | 36 ± 1.6 (29) | 41 ± 1.6 (20) | 2.21, 0.056 | 37 ± 1 (43) | 40 ± 1.6 (29) | 1.64, 0.20 |
| AP amplitude, mV (▾) | 53 ± 1 (29) | 50 ± 1 (20) | 1.23, 0.39 | 53 ± 1 (43) | 50 ± 1 (29) | 2.01, 0.090 |
| Δ RMP/AP amplitude, mV (Δa) | 134 ± 1.6 (29) | 131 ± 2 (20) | 1.01, 0.53 | 134 ± 1 (43) | 128 ± 1.5 (29) | 2.64, 0.018 |
| Δ AP threshold/AP amplitude, mV (Δc) | 97 ± 2 (29) | 90 ± 2 (20) | 2.20, 0.059 | 97 ± 2 (43) | 88 ± 2 (29) | 2.94, 0.0078 |
| AP halfwidth, ms (↔) | 0.66 ± 0.01 (29) | 0.68 ± 0.02 (20) | 0.76, 0.70 | 0.68 ± 0.02 (43) | 0.70 ± 0.02 (29) | 0.62, 0.79 |
Table lists mean ± SEM (sample size) for passive and active properties of core and shell MSNs for both naive and rewarded rats. Statistics for core versus shell comparisons were obtained from Sidak’s post hoc test (t value, p value) and mixed-effects model planned comparisons (F value, p value). Main effects and interactions are detailed in Table 2.