Presentation Information
[P1-21]Interaction between timing, stimulus control of light and sound, and its effects on anticipatory responses in multiple and mixed fixed interval schedules in rats (Preliminary Results)
*Paulina Citlali Montoya Barragán1, Heber Zapata2, Jonathan Buriticá1 (1. CEIC, UDG (Mexico), 2. UACH (Mexico))
Keywords:
post-reinforcement pause,fixed intervals,discriminative stimuli,timing,rats
The post-reinforcement pause has been studied using fixed-ratios in mixed and multiple schedules. The results showed long pauses in the multiple schedule with the long component and short pauses in the mixed schedule for both components, suggesting that the pause is a function of the upcoming ratio. This study aimed to analyze timing in rats under mixed and multiple fixed-interval (FI) reinforcement schedules with short and long intervals, using the same methodology of the fixed ratio comparisons, to replicate that pauses are anticipatory in the FI schedules as well and to collect evidence about how the behavioral patterns under control of the stimuli may facilitate timing. In Experiment 1, four rats underwent four phases of 20 sessions, alternating between mixed and multiple schedules. One component in each schedule was FI-60 s (short) and the other FI-240 s (long), presented in a semi-random sequence. The reinforcement was 5 seconds of access to water. Experiment 2 followed a similar procedure with five rats, using FI-30 s (short) and FI-120 s (long). The sessions were recorded for analysis. Additionally, two phases with peak trials were included. The results suggest differences in response rate between FIs, as well as between schedules and components. Stimulus control was observed in the multiple schedule (by the interaction of time and sound/light) and mixed schedules (by time). Furthermore, the pause's duration increased with the interval's length. It is concluded that the pause is an anticipatory phenomenon and that the rats use elapsed time as a signal to anticipate the delivery of the reinforcer; they combine such information with the stimulus to more effectively time appropriate durations. Additionally, videos were automatically analyzed using a deep learning model to track behavioral patterns. The results and conclusions of this study are preliminary.