Discrimination of serial auditory patterns in rats : roles of configural and elemental associations

Abstract

In order to test whether rats could discriminate between tone sequences, food deprived rats were given appetitive discrimination conditioning with repeated ascending or descending series of musical notes serving as conditioned stimuli (CSs). The other type of tone sequence was reinforced as the other was followed by nothing. In Experiment 1, each series of 8 tones formed a 2 s cycle. The cycle was repeated six times so that the duration of the whole sequence was 12 s. In Experiment 2, the CSs were similar to those in Experiment 1 except that they started with a random note. As a result, rats could discriminate between the stimuli when the CS started systematically with the same note. When the starting note of the CS was randomized rats could not make the discrimination. Thus, according to this study, in a discrimination learning paradigm with serial auditory compounds rats probably form an association between the first tone and the US (or lack of it) but not with the serial pattern and the US.