Fig. 9.

The specificity of each animal’s memory for frequency was tested via stimulus generalization during extinction following their final training session. No significant differences were observed between any of the groups. The generalization test used seven frequencies, including the CS+, Low CS− and High CS−. Gradients were sharp with the vast majority of responses made to the CS+ or to its adjacent higher frequency (7.7 kHz, 0.63 octaves away). Few responses were made to the CS− or other tones. There were no significant differences between groups.