Discrimination training affects stimulus generalization in mice during Pavlovian eyeblink conditioning

Abstract

Abstract The delicate balance between generalization and discrimination of responses is crucial for survival in our ever-changing environment. In particular, it is important to understand how stimulus discrimination affects the level of stimulus generalization. For example, when we use non-differential training for Pavlovian eyeblink conditioning to investigate generalization of cerebellar-related eyelid motor responses, we find generalization effects on both amplitude and timing of the conditioned responses. However, it is unknown what the generalization effects are following differential training. We trained mice to close their eyelids to a 10kHz tone (CS+) while alternatingly exposing them to a tone frequency of either 4kHz, 9kHz or 9.5kHz (CS-). We tested the generalization effects with tones ranging from 2kHz to 20kHz. Our results show that the level of generalization tended to positively correlate with the difference between the CS+ and the CS- training stimuli. These effects of generalization were only found for the probability and amplitude of the conditioned responses, but we did not find any significant effect on the onset of the conditioned eyelid responses. These data highlight the specificity of the generalization effects following differential versus non-differential training.