Figure 2.

Eyeblink conditioning paradigm (a) and behavioral data (b–d). Group mean CR incidences and SEs are shown in the top row, individual eyelid traces in the second row, and averaged traces of the same subject in the third row. b, Unpaired phase: the tone-CS does not elicit eyeblinks, whereas the air puff-US is consistently followed by eyeblinks. c, Acquisition phase: paired CS-US trials are shown on the right and CS-only trials interspersed in paired trials on the left. Conditioned responses which start after CS onset and before US onset are clearly seen. d, Extinction phase: CS-only extinction trials are shown in two blocks of 10 trials and one block of five trials. Decline of CR incidence is clearly seen. tr, Trial.