Effects of REM sleep deprivation on a multiple schedule of appetitive reinforcement

The effects of rapid eye movement sleep deprivation (REMSD) on appetitively reinforced responding by rats was studied in two experiments. In Experiment 1, a lever press was maintained on a baseline multiple FR 30 FI 60-s schedule of reinforcement that was reestablished after each experimental manipulation. Animals were then repeatedly exposed to 24, 48, or 96 h of REMSD and equivalent periods of tank control and cage control conditions. For all animals responding was reduced only after 96 h of REMSD, but tolerance to REMSD developed following repeated exposures. Experiment 2, replicated the procedures of Experiment 1 except that the apparatus was modified to prevent ad libitum access to REMSD during operant sessions. Animals were repeatedly exposed to 96 h of REMSD and equivalent periods of tank control and cage control conditions. No reduction in responding was observed in Experiment 2. The current findings, in conjunction with previous research, suggest that REMSD may have qualitatively different effects on responding maintained by positive versus negative reinforcement.