Figures 7B, 7D, and 7F with Figures 5A, 5C, and 5E). As for normal animals, the firing rate could increase or decrease with either signal such that the average tuning curve across check details all units was nearly flat (cf. Figures 7C, 7E, and 7G with Figure 5B, 5D, and 5F). Also, as in normal animals, the mean rate of neurons that encoded amplitude was significantly related to the slope of the rate versus amplitude curve, with a mean firing rate of 22 Hz for cells that increased their firing rate with amplitude and 7.0 Hz for cells that decreased their firing rate with

amplitude (Figure 7B). These data show that the signatures of vibrissa motion in vM1 cortex do not require sensory feedback through the trigeminal nerve. Lastly, the mean firing rate during whisking was greater in transected versus normal animals (cf. Figure 7H with Figure 5G), and this was matched by a similar increase in the average slopes Autophagy screening of the tuning curves λ(θamp) and λ(θmid). As a consequence of this balance the population analysis was essentially the same in

the case of transection (Figure S7). We have addressed the issue of coding vibrissa position in head centered coordinates. Two timescales are involved, a slow, ∼1 s scale associated with changes in the amplitude and midpoint of the envelope of whisking motion and a fast scale associated with rhythmic variation in position (Figure 2 and Figure 3). We find that a majority of single units in vM1 cortex code for variation in amplitude and midpoint, while a minority of units coded the phase of whisking (Figure 4). None of these signals are abolished or modified by a total block of the trigeminal sensory input, implying that they are generated by a central source (Figure 7). The modulation of the firing rate of

different units in vM1 cortex by the slowly evolving parameters of whisking is strong (Figure 4). Yet, the firing rates of these cells are low so that the contribution of individual units to decoding is low (Figure 5 and Figure 6). This situation is similar to the case of units that code the direction of arm movement in motor cortex in Sitaxentan monkey (Schwartz et al., 1988). Nonetheless, our ideal observer analysis shows that populations of a few hundred such cells can report the amplitude and midpoint of the vibrissae with a less than 5% error (Figure 6). We chose to extract the amplitude, midpoint, and phase of whisking with a modified Hilbert transform (Figure 3A). This method is sensitive to changes in the phase, as opposed to the assumption of linear phase when fitting a sinusoid and offset to each whisk (Curtis and Kleinfeld, 2009, Gao et al., 2001 and Leiser and Moxon, 2007). The decomposition of the whisking trajectory into these parameters appears to be behaviorally relevant (Figure 3). Further, except for rare occurrences such as double pumps, i.e.