Figure 2. Behavior and Neuronal Activity in a Typical Trial.

(A) Spatial arrangement of the two high-speed cameras.

(B) Images from high-speed films taken from two different views (top row—top view, bottom row—side view, see [A] for positions; frame pairs of the upper and lower rows are synchronous). Whisker C2 is traced. Although in the side view, the rat's snout seemed to touch the texture, the corresponding top view frames show that this was not the case. Although on a small proportion of trials, rats were close enough that microvibrissae contact could not be excluded, this happened too rarely to explain the animals' high performance.

(C) Spikes fired by a neuronal cluster whose receptive field was centered on whisker C2. Estimated moment of choice is given by gray vertical line at 0 ms. Contacts of the selected whisker before decision are marked as red frames. Note the increase in firing rate during contact. Contacts after choice are not highlighted, and the corresponding spikes were not considered in the analysis. Shown: rat 16, session 2006-07-23, cluster #58, trial 20, smooth texture.