Fig. 3.

Layer-specific dynamical neuronal modulations. Each colored circle depicts simultaneously the fraction of facilitated (Fac) and suppressed (Sup) neuronal firing rate modulations in a 10-ms bin. Neuronal state maps calculated for layers II/III (yellow circles), layer IV (black circles), and layers V/VI (red circles) are presented. As depicted in gray in A, from top to bottom and left to right, the 4 quadrants indicate firing rate modulations that are prominently: Q1, suppressed; Q2, suppressed and facilitated; Q3, no firing modulations; and Q4, facilitated. A–J: different trajectories of neuronal state maps of granular, supragranular, and infragranular layers are clear in A and B. Additionally, note that in G–J (which are associated with intense whisker stimulation) a large fraction of neuronal firing modulations recorded from layer IV are in the lower right quadrant (facilitated responses), whereas very different neuronal firing modulations occur in layers V/VI (which initially are in the facilitated responses quadrant but gradually shift toward the suppressed quadrant; Q4 to Q1). K: Euclidean distances between neuronal state maps of different S1 layers. As suggested by the different trajectories in the state maps, the largest Euclidean distances between neuronal state maps of layer IV and neuronal state maps of layers V/VI (highlighted red line) were found during the anticipatory (−0.5-0 s) and the reward period (1.0–2.0 s), where the firing rate modulations concentrated in different quadrants for long periods. Euclidean distances between neuronal state maps of layers II/III and layer IV (black line) were maximal during the anticipatory period. Euclidean distances between neuronal state maps of layers II/III and layers V/VI (gray line) were maximal during the anticipatory period. Neuronal state maps of all layers presented minimal Euclidean distances during the discrimination, animal behavioral response, and at the beginning of the reward period.