Physiological Changes Associated with Changing Fixed Ratio Schedules in Rats

Publisher Website
Google Scholar
Abstract
In two experiments rats, which had been gradually adjusted to a fixed ratio 50 (FR 50) reinforcement schedule over 10 sessions and then suddenly were placed on a FR 125 schedule on Session 11, showed a significant decrease ( p < .05) in circulating blood eosinophil levels compared to groups which had been similarly shaped up to but maintained on a FR 50 schedule. The changes presumably occurred within a 35- to 40-min. period following the schedule change. Significant positive correlations were noted between the amount of disruption in the response pattern observed in the records of the group that had been shifted from FR 50 to FR 125 and number of fecal boluses on the last day, duration of the bar-press per response, and thyroid-thymus nodule weights.