The influence of reinforcement schedule on experience‐dependent changes in motivation

Abstract

The progressive ratio procedure is used across fields to assess motivation for different reinforcers, define the effects of experimental interventions on motivation, and determine experience‐dependent changes in motivation. However, less is known about how operant training schedules affect performance on this widely utilized task. Here we designed an experiment to examine the effect of variable ratio versus fixed ratio training schedules of reinforcement on progressive ratio performance while holding other performance variables constant between groups. We found a robust increase in maximum ratio completed between the pretest and posttraining test highlighting a robust training effect on progressive ratio performance. However, it did not matter if the training was under a fixed or variable ratio schedule. Additionally, we show that neither individual rates during training nor extinction responding correlated with maximum ratio achieved during the sessions. Finally, we show that rates during the training sessions do correlate with extinction performance, suggesting that these variables measure a different aspect of performance that does not predict motivation.

Intense long‐term training impairs brain health compared with moderate exercise: Experimental evidence and mechanisms

“…PR tasks are used to analyze motivation for various reinforcers, that is, the willingness of the organism to exert effort in order to obtain a reward. 29 In our work, the number of responses required to earn a food pellet in the PR experiments escalated as follows: 1‐2‐3‐5‐12‐18‐27‐40‐60‐90‐135‐200‐300‐450‐675‐1000. The PR session was performed only once and lasted for 2 h or until rats failed to complete the response requirement for delivery of a reinforcer within 1 h. The breakpoint for the extinction of food‐maintained operant behavior was determined for each animal.…”

“…PR tasks are used to analyze motivation for various reinforcers, that is, the willingness of the organism to exert effort in order to obtain a reward 29 . In our work, the number of responses required to earn a food pellet in the PR experiments escalated as follows: 1‐2‐3‐5‐12‐18‐27‐40‐60‐90‐135‐200‐300‐450‐675‐1000.…”

Sensitivity to outcome devaluation in operant tasks is better predicted by food restriction level than reinforcement training schedule in mice

“…Both the preferential reinforcement of long inter-response times (IRT) in RI schedules (Krame & Rilling, 1970; Kuch & Platt, 1976) and the stronger action-outcome correlation in RR schedules (Dickinson, 1985; Ferster & Skinner, 1957; Pérez et al, 2019 although see Garr et al, 2020) are thought to contribute to generating this difference, and our finding that response rates are more sensitive to food restriction level in mice trained on RR schedules compared to RI schedules complements these interpretations. Furthermore, previous work has shown that while training schedule has little effects on motivation (Johnson et al, 2022), food restriction levels do impact it (Dietze et al, 2016; Malikovic et al, 2018). By manipulating food restriction levels, our findings provide further support to the notion that the ability to control one’s own reinforcement rate explains the difference in response rates generated by RR and RI schedules.…”

CRF release from a unique subpopulation of accumbal neurons constrains action-outcome acquisition in reward learning

“…After reaching criteria at FR3, mice were tested in a 1-day progressive ratio task. The progressive ratio task was based on a protocol modified for mice by Johnson et al (2022 35 ), but with a maximum session time of 30 min. Mice were excluded if they failed to reach criteria after 10 days.…”