Wheel running induced by intermittent food schedules

Abstract

Sixteen naïve male Wistar rats were exposed to intermittent food delivery to measure the development of schedule-induced wheel running, using fixed time (FT) 30, 60, 120, 240 and 480 s schedules, counterbalanced across animals according to a Latin square design (except under the FT 480 s, which was always presented last to complete the data set). Rats were also exposed to a massed-food control condition. Wheel running was induced in the range of 30-240 s with a gradation as a function of inter-food interval (IFI) length. The temporal distribution of wheel turns was generally presented in the form of an inverted U-shaped as IFIs progressed, showing maximum responding during the first portion of the interval. The introduction of massed-food resulted in an immediate reduction in wheel running. These results support the notion that wheel running can be schedule-induced and categorized into the so-called adjunctive behaviors. These data indicate that IFI length affects the development of schedule-induced wheel running and that the rate of wheel running is maintained by intermittent reinforcement, which are common characteristics of schedule-induced behaviors. Likewise, this idea is supported by the occurrence of a similar temporal pattern to that found with other adjunctive behaviors, such as schedule-induced polydipsia, with its maximum manifestation occurring between the beginning and middle of IFIs.

Effects of pre‐operant running and sucrose concentration on operant wheel running on a fixed interval schedule of reinforcement

“…The pattern of wheel running observed on the FI schedule without pre‐operant running (0‐min pre‐operant run) has similar features to that observed by Gutiérrez‐Ferre and Pellón (2019) for wheel running on fixed time (FT) schedules of food delivery. Ten‐week‐old male Wistar rats were exposed to FT 30, 60, 120, 240, and 480 s schedules in their home cages with attached running wheels.…”

“…Instead of functioning as reinforcement, sucrose presentation seemed to induce an increase in wheel revolutions. As was the case with the 0‐min pre‐operant running condition of Experiment 1, the wheel‐running pattern induced by sucrose presentation has similarity to the adjunctive wheel running on FT schedules of food delivery as described by Gutiérrez‐Ferre and Pellón (2019).…”

“…The pattern of a rise, decline, and plateau on the FI schedule for no pre‐operant running in the current study, together with operant wheel running on FI 15‐, 30‐, and 60‐s schedules in Belke et al’s (2018) study, have some resemblance to Gutiérrez‐Ferre and Pellón's (2019) patterns. Across FI 15‐, 30‐, and 60‐s schedules of Belke et al, wheel revolutions increased from 0‐9 s, peaked at 9‐12 s then decreased slightly and remained at a constant level throughout the remainder of the FI interval for each schedule.…”

“…Skinner and Morse (1958) did not use a wheel brake and noted a decline in wheel running just prior to sucrose delivery. Gutiérrez‐Ferre and Pellón (2019) showed that running decreased throughout the FT interval toward the time of food delivery. In both cases, food delivery served as a temporal marker that affected wheel running.…”

Matching, induction, and covariance with mixed response‐contingent food and noncontingent food

“…Response-contingent food increases (induces) the activity with which it covaries-"operant" activity. Food presentation-both contingent and noncontingent-also induces activities often called adjunctive activities (Falk 1971(Falk , 1977; see also Staddon, 1977), which may compete with the operant activity (Baum & Aparicio, 2020;Gutiérrez & Pell on, 2019). Operant activity is well-known to conform to basic matching theory (deVilliers, 1977;Herrnstein, 1970), but experiments that include both response-contingent food and noncontingent food require some extensions to matching theory, consistent with the generalized matching law or Law of Allocation (Baum, 1974;Baum & Aparicio, 2020;Rachlin & Baum, 1972).…”