3 ± 3.0 mV; median 6.7 mV; range 0.5 to 11.0 mV); latency (mean 8.6 ± 2.7 ms; median 8.7 ms; range 5.3 to 12.7 ms); time-to-peak (mean 16.0 ± 9.9 ms; median 13.8 ms; range 4.9 to 37.2 ms); duration (mean 52.5 ± 27.0 ms; median 51.8 ms; range 9.1 to 103.1 ms); and rate of rise (slope, mean 0.56 ± 0.49 V/s; median 0.41 V/s; range 0.09 to 1.52 V/s) (Figures 4B). Cells with shorter latency tended to exhibit larger-amplitude subthreshold responses and neurons exhibiting a fast time-to-peak also tended to have a shorter-duration response (data not shown). Neurons recorded deeper DAPT supplier in L2/3 responded with PSPs of larger-amplitude depolarizations, shorter latencies, shorter-duration

responses, and faster rates of rise (PSP slope) (Figure 4B). Therefore, deeper neurons, located

in layer 3, preferentially signal each individual contact with high temporal precision, whereas the more superficial layer 2 neurons preferentially integrate touch responses over a longer timescale. Nine identified layer 2/3 pyramidal neurons were recorded in adjacent barrel columns (Table S1). The grand averaged response to active touch of the C2 whisker with an object reveals a smaller amplitude response with longer latency in the surrounding cortical columns, but otherwise sharing a similar range of response properties (Figure S2). That the touch response spreads to neighboring columns is consistent with voltage-sensitive dye imaging data showing that a large area

of cortex can depolarize in response to single whisker active touch in awake mice RAD001 in vivo (Ferezou et al., 2007). These data are also consistent with the broad subthreshold receptive fields of layer 2/3 neurons evoked by passive whisker deflection recorded under anesthesia (Moore and Nelson, 1998, Zhu and Connors, 1999 and Brecht et al., 2003). Consecutive touches evoked different amplitude touch PSP responses (Figure 5A) (coefficient of variation mean ± SD 1.4 ± 0.7; median 1.0; range 0.4 to 3.1). Part of the variability of the touch response could be accounted for by considering the neuronal membrane potential immediately preceding the response onset, which profoundly influenced the PSP amplitude. Touch responses evoked at spontaneously hyperpolarized precontact Vm were larger in amplitude Non-specific serine/threonine protein kinase compared to touch responses occurring during spontaneously depolarized membrane potentials (Figure 5B). Indeed, at the most depolarized precontact membrane potentials, the touch response was hyperpolarizing (Figure 5B). Plotting the active touch response amplitude as a function of the precontact Vm revealed a close to linear relationship (Figure 5C). The correlation between response amplitude and precontact Vm was significant (α = 0.05) in all 17 neurons tested (cell #36 had a complex depolarizing-hyperpolarizing response and was not included in the subsequent active touch response dynamic analysis; see Table S1). The mean coefficient of correlation was −0.