We found that a simple integrate and fire model applied to the subthreshold activity

was sufficient to explain deprivation-induced changes in suprathreshold activity. The membrane voltage distribution was shifted by the amount of depolarization EGFR inhibitor (method 1) or recalculated for each time step around stimulation (method 2). The probability of firing was then calculated and used to create a predicted PSTH, which could be compared to the real PSTHs (see Figure S2). The exact shapes of the PSTHs were not closely reproduced for IB cells, but the effects of sensory deprivation were. The complex time-specific modifications observed for RS cells were also reproduced by the model. In conclusion, changes observed in suprathreshold activity

directly MG-132 reflected changes at the subthreshold level, which implies that synaptic and not spike generation mechanism explain the observed plasticity. As whisker deprivation affected the timing as well as the amplitude of the responses to whisker stimulation, we analyzed the time course of response for RS and IB cells. Figure 5 represents averaged wPSPs and PSTHs for one trimmed and one spared whisker only. Note that the early spikes (<15 ms poststimulus) were significantly depressed for PW stimulation in the IB cell population GBA3 (t(38) = 3.2, p < 0.005; see Figure S1), but not for the other trimmed whiskers, as

revealed in Figure 5A. The potentiation in IB cells and the depression in RS cells appear to be roughly uniform throughout the whole time course of the response. In contrast, depression of PW responses in IB cells was greater in the early part of the response (<30 ms poststimulus). Similarly for RS cells, the best spared whisker was potentiated for the early part of the response (<25 ms poststimulus) but depressed for the late component. The latter observation held when all the spared whiskers were considered. We quantified the area of the subthreshold response in four time windows (0–25; 25–50; 50–75; 75–100 ms poststimulus) and the suprathreshold response in three time-windows (0–15; 15–30; 30–45 ms poststimulus). RS cells’ response to spared whisker stimulation displayed a significant interaction between deprivation and time both for suprathreshold (F(2,2) = 6.8, p < 0.005) and subthreshold (F(3,3) = 5.5, p < 0.005) parameters. These data suggest that the early component of the response can be potentiated (as with the RS cells) or depressed (as with the IB cells) independently of later components of the wPSP. Latency and jitter of evoked action potentials are important temporal parameters for coding sensory information.