Fig. 8.

Rasters and spike density plots of the activity of one neuron that responded to the appearance of the schedule fraction cue. A, B, Vertical lines(y-axis) indicate the onset of the appearance of the cue. Upper rows indicate the rasters, andlower rows indicate the spike density plots. The responses are aligned to the onset of the cue. A, Neuronal response in brightening paradigm sorted by the schedule fraction. The neuron responded in 2/3, 3/3, and 2/2 conditions.B, The responses of the same neuron in random paradigm sorted by the cue brightness. The plots compare the schedule fraction with the corresponding brightness in the brightening paradigm (connected by the heavy arrows). The neuronal responses, which had been large in the 2/3, 3/3, and 2/2 conditions of the brightening paradigm, disappeared at the corresponding cue brightness in the random paradigm.