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. 2003 Oct 29;23(30):9937–9946. doi: 10.1523/JNEUROSCI.23-30-09937.2003

Figure 3.

Figure 3.

Voltage-dependent amplification of near-threshold membrane potential oscillations in the vSUB RS and BS neurons after withdrawal from repeated saline or amphetamine treatment. A shows the voltage–dependent amplification of subthreshold membrane potential oscillations measured as average deviation before (Baseline) and after TTX (500 nm). B, The power spectral density plot of the subthreshold membrane potential oscillations from pooled RS and BS vSUB neurons (n = 15) in nontreated and SAL controls, showing a voltage-dependent peakat 3 Hz at –55 mV and its attenuation after TTX (500 nm). C and D show a scatter plot of the average deviation of the RS and BS membrane potential oscillations at several holding potentials (–75 to –55 mV) in the SAL/EW (C) and AMPH/EW (D) early withdrawal groups. Open (SAL) and filled (AMPH) squares represent the pooled RS and BS values for each treatment group. E shows that both treatment groups show a significant voltage-dependent amplification of the membrane potential oscillations (SAL/EW, n = 15, p < 0.001; AMPH/EW, n = 19, p < 0.001; see Appendix). Scatter plots for the late withdrawal are not shown because there were no differences between treatment groups, and the scatter between RS and BS neurons was similar to the early withdrawal time (C, D). E and F show the pooled average of RS and BS neurons for each treatment group. Compared with SAL/EW, the AMPH/EW group had significantly decreased voltage-dependent amplification of the membrane potential oscillations in the near-threshold voltage range between –60 and –55 mV (E) (*p < 0.05). TTX (500 nm) greatly reduced voltage-dependent oscillation amplification and eliminated the drug-treatment differences. F, Late withdrawal voltage-dependent amplification of the membrane potential oscillation amplitude in the SAL/LW (n = 17) and AMPH/LW (n = 15) groups before and after attenuation by TTX. Symbols represent the mean average deviation and holding potential; error bars represent ± SEM average deviation. Peak-to-peak oscillations were 2–10 times larger than the average deviation for each trace.