Different types of MC neurons activated during classical blink conditioning with a delay paradigm. A, B, Firing properties of type A neurons. A, From top to bottom are illustrated the conditioning paradigm, the raw activity of a representative type A neuron, the event channel and firing rate of the selected neuron, and the raw EMG activity of the orbicularis oculi (O.O.) muscle during a single CS–US presentation. B, Conditioning paradigm, raster plot of all spikes collected from the same MC neuron during 15 successive trials, and the averaged firing rate. Type A MC neurons were characterized by an increased firing rate before the CR and a noticeable decrease of their firing rates during US presentation. C, D, Same as in A and B for a representative type B MC neuron recorded for 26 trials. Type B neurons were characterized by an initial firing peak preceding the CR and by a second increase of firing rate during US presentation. E, F, Same as in A and B for a representative type C MC neuron recorded for 53 trials. Type C neurons were characterized by a continuous increase in their firing rates preceding the CR and by reaching the maximum peak during US presentation. Time calibration in E is also for A and C. Time calibration in F is also for B and D.