Relationship between magnitudes of conditioned responses and PC responses during the first 2 s of CS presentations in the acquisition sessions. A. Representative data from a fish that showed an significant correlation (p = 0.002) between the conditioned response magnitude and the level of suppression of PC activity during the CS. B. Representative data from a fish that did not show a correlation between the magnitude of the conditioned response and the response of the PC to the CS. The vertical axes show relative spike frequencies of the PCs relative to the frequencies in the 2 s before the CS. Inhibitory responses of the PCs to the CS were assigned negative values. Formulae of the linear regressions and r-values were also shown. PC: Purkinje cell; CS: conditioned stimulus.