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Published on: September 3, 2015
Early Life Maternal Separation and Maternal Behaviour Modulate Acoustic Characteristics of Rat Pup Ultrasonic
Jasmine H Kaidbey1, Manon Ranger2, Michael M Myers3
1Department of Psychiatry, Developmental Neuroscience, Columbia University Irving Medical Centre, New York, NY, 10032, USA. jhk2185@cumc.columbia.edu.
Insights
Early maternal separation in rats alters ultrasonic vocalizations during isolation, indicating a heightened stress response. This research models neurodevelopmental impacts and potential interventions for early life stress.
Area of Science:
- Neuroscience
- Behavioral Biology
- Developmental Psychology
Background:
- Early life stress, including maternal separation, can lead to adverse long-term neurodevelopmental outcomes.
- Understanding the immediate behavioral responses to separation is crucial for identifying vulnerable periods and mechanisms.
Purpose of the Study:
- To investigate the impact of daily maternal separation (MS) on rat pups' neurobehavioral responses to isolation.
- To analyze ultrasonic vocalizations (USV) as a measure of stress response in pups subjected to MS.
Main Methods:
- Rat pups underwent daily maternal separation from postnatal days 2-10.
- Ultrasonic vocalizations were recorded during two isolation periods at postnatal day 12, before and after maternal reunion.
- Acoustic characteristics of USVs were analyzed and compared between MS and control groups.
Main Results:
- MS pups showed altered USV patterns in the second isolation period, with a higher proportion of high-frequency calls.
- Control pups increased low-frequency calls after reunion, while MS pups showed the opposite pattern.
- Maternal care levels differentially modulated pup USVs in control versus MS groups.
Conclusions:
- Maternal separation alters ultrasonic vocalization patterns, suggesting an increased stress response to isolation.
- This study provides a translational model to explore mechanisms and interventions for mitigating negative effects of early life stress.
Abstract:
Early separation of preterm infants from their mothers has adverse, long-term neurodevelopmental consequences. We investigated the effects of daily maternal separation (MS) of rat pups from postnatal days 2-10 (PND2-10) on neurobehavioural responses to brief isolation at PND12 compared with pups receiving controlled handling without MS. Ultrasonic vocalizations (USV) were measured at PND12 during two, 3-minute isolations occurring immediately before and after a 3-minute maternal reunion. There were no significant differences in acoustic characteristics between MS and control animals in the first isolation. However, in the second isolation, MS pups produced a greater proportion of high (~60 kHz) vs low (~40 kHz) frequency calls. During this isolation, control pups made longer and louder low frequency calls compared to the first isolation, whereas MS pups did the opposite. Maternal behaviour of control and MS mothers modulated pup acoustic characteristics in opposite directions; higher maternal care was associated with more low frequency calls in control pups but more high frequency calls in MS pups. We hypothesize that MS results in USV emission patterns reflective of a greater stress response to isolation. This translational model can be used to identify mechanisms and interventions that may be exploited to overcome the negative, long-term effects of MS.
