Effects of shifts in food reinforcement context on rats’ consumption of concurrently available water or sucrose solution

Abstract

The purpose of this study was to investigate the effects of signaled transitions from relatively rich to lean conditions of food reinforcement on drinking concurrently available water or sucrose-sweetened water in rats. Past research demonstrated that these negative incentive shifts produce behavioral disruption in the form of extended pausing on fixed-ratio schedules. Four male Long-Evans rats operated on a two-component multiple fixed-ratio fixed-ratio schedule. In one manipulation, the ratio was held constant and the components arranged either a large six-pellet reinforcer (rich) or small one-pellet reinforcer (lean). In a second manipulation, the components both produced a one-pellet reinforcer but differed in terms of the ratio requirement, with the rich and lean conditions corresponding to relatively small and large ratios. In both manipulations, components were pseudorandomly presented to arrange four transitions signaled by retractable levers: lean-to-lean, lean-to-rich, rich-to-rich, and rich-to-lean (the negative incentive shift). During experimental conditions, a bottle with lickometer was inserted in the chamber, providing concurrent access either to tap water or a 10% sucrose solution. The negative incentive shift produced considerably more drinking than the other transitions in all rats during both manipulations. The level of drinking was not polydipsic; rather, it appears that the negative incentive shift enhanced the value of concurrently available reinforcers relative to food reinforcement.

Effects of negative incentive shifts in food reward on rats' consumption of concurrent ethanol solutions

“…Consistent with general findings by Galuska and Sawyer (2017), extended pausing during the negative incentive shift was most robust with access to the sucrose solution. For each rat in each condition, the median (and IQR) pause duration and running response rate per transition were calculated and shown in Tables 1 and A1, respectively.…”

“…Based on the procedure developed by Perone and Courtney (1992), Galuska and Sawyer arranged a multiple FR FR schedule. Galuska and Sawyer (2017) found that, consistent with past findings, the negative incentive shift produced behavioral disruption as indexed by extended pausing. Components were signaled by retractable levers, such that insertion of the left lever was correlated with the large magnitude reinforcer and insertion of the right signaled the small.…”

“…Following preliminary training, the method used by Galuska and Sawyer (2017) to arrange shifts in food reinforcer magnitudes, based on the general procedure developed by Perone and Courtney (1992), was used throughout this study. Following preliminary training, the method used by Galuska and Sawyer (2017) to arrange shifts in food reinforcer magnitudes, based on the general procedure developed by Perone and Courtney (1992), was used throughout this study.…”

“…In addition to pigeons (Perone & Courtney, 1992;Retzlaff, Parthum, Pitts, & Hughes, 2017), the effect has been shown in rats working for food (Galuska & Sawyer, 2017;Galuska & Yadon, 2011) and with components varying in force required to execute a lever press (Wade- Galuska, Perone, & Wirth, 2005), domestic hens with reinforcer delay (Harris, Foster, Levine, & Temple, 2012), monkeys responding for self-administered cocaine doses (Galuska, Wade-Galuska, Woods, & Winger, 2007), and humans working for money (Bejarano, Williams, & Perone, 2003;Williams, Saunders, & Perone, 2011) and while transitioning between preferred to less-preferred activities (Jessel, Hanley, & Ghaemmaghani, 2016). In addition to pigeons (Perone & Courtney, 1992;Retzlaff, Parthum, Pitts, & Hughes, 2017), the effect has been shown in rats working for food (Galuska & Sawyer, 2017;Galuska & Yadon, 2011) and with components varying in force required to execute a lever press (Wade- Galuska, Perone, & Wirth, 2005), domestic hens with reinforcer delay (Harris, Foster, Levine, & Temple, 2012), monkeys responding for self-administered cocaine doses (Galuska, Wade-Galuska, Woods, & Winger, 2007), and humans working for money (Bejarano, Williams, & Perone, 2003;Williams, Saunders, & Perone, 2011) and while transitioning between preferred to less-preferred activities (Jessel, Hanley, & Ghaemmaghani, 2016).…”

“…In Experiment 1, the general procedure of Galuska and Sawyer (2017) was extended to ultimately present a concurrent, freely available 10% ethanol solution (v/v). The purpose of this study is to assess whether negative incentive shifts in food reward engender oral ethanol self-administration in rats.…”