The effects of 24-hr maternal separation and of litter-size reduction on the isolation-distress response of 12-day-old rat pups

摘要: We asked whether the mother–infant interaction acted over time to regulate ultrasonic vocalization (USV) and activity responses of 12-day-old rat pups isolation in a novel test area. In series four experiments, we found that 24 hr maternal deprivation did not alter USV responses, but reduction litter size 4 from 8 markedly attenuated response increased weight gain, without effects on level. Ambient temperatures during 24-hr separation were varied 23° 35°C effect subsequent levels reduced separated at low heat Possible mechanisms for regulation involving nutrient effects, altered processing thermal stimuli, inhibition thermogenesis by are discussed. © 1993 John Wiley & Sons Inc.