Fig. 17.

Summary of physiological findings supporting layer-specific dynamics in tactile discrimination. A: schematics of physiological findings present in state maps from neurons recorded across S1 layers in awake behaving rats performing a tactile discrimination task. Left: when rats were sampling an aperture, all layers presented mostly excited firing rates (+), similar to what was observed in neurons recorded from VPM (red encasing in all layers). Right: during the reward period (which was also characterized by intense whisker stimulation), neurons recorded from layers V/VI alone presented suppressed firing rates (−), as observed in neurons recorded from POM (green encasing only in layers V/VI). Inactivation of M1 or contralateral S1 demonstrated that cortical loop modulations accounted for multiple firing rate dynamics across all periods of the task. M1 inactivation affected facilitated firing rate modulations, contralateral S1 served as a switch between lemniscal and paralemniscal modes of processing, and M1 and contralateral S1 jointly controlled suppressed modulations. B: table with the main differences found in firing rate modulations (F.R.), neuronal dynamics (i.e., state maps), amount of information encoded across structures, and causal transfer of information between structures. Ant, anticipatory firing rate modulations; Sup, suppressed; Fac, facilitated; Mag, magnitude; Dur, duration.