Abstracts

Febrile convulsions are common among human neonates, and have been studied extensively with rat pups, typically by heating the pups to ~43 C. Pups subjected to febrile convulsions exhibit enhanced susceptibility to kindling and exhibit behavioural changes as adults. The changes in behaviours include impairments in spatial cognition and increased anxiety in novel situations. The present study examines whether or not behavioural change can be observed in neonates following convulsions. As pups are unable to regulate body temperature for the first two weeks of life, they rely on their mother and littermates for warmth. Pups emit ultrasonic vocalizations (20-40 KHz) when their body temperature is too low, signaling their mother to return them to necessary warmth. The behaviours examined in this experiment included mother-pup interactions (pup retrieval, anogenital licking, nursing, grooming) and ultrasonic vocalizations produced by the pup. It was predicted that mothers would decrease maternal behaviours, specifically retrieval, towards febrilely convulsed pups, and that febrilely convulsed pups would not vocalize as often as their littermate controls.
Convulsions were induced with the use of a heat lamp on P8, littermate control pups were removed from the mother for the same duration. On P15, mothers and pups were placed in a translucent cage and mother-pup interactions were videorecorded for 20 minutes. Following the recording of mother-pup behaviours, ultrasonic vocalisations by the pups were individually monitored.
[italic]Mother-pup interactions: [/italic]Analyses ([chi]2) indicated that mothers retrieved convulsed pups less frequently than control pups. However there were no significant differences between control and convulsed pups in the frequency of maternal grooming, nursing, or anogenital licking.
[italic]Ultrasonic Vocalisations: [/italic]Although there was no significant difference in the frequency of ultrasonic vocalisation between control and convulsed pups, there were qualitative differences in vocalizations between the groups. Notably, control pups emitted longer vocalisations that were of greater magnitude than did convulsed pups.
Consistent with the predictions, there were differences in mother-pup interactions between convulsed and control groups. As these groups were littermates it is difficult to attribute these differences to the individual skill of the mother. Further, there were qualitative differences to the ultrasonic vocalizations between the convulsed and control groups, which may have influenced maternal behaviours. Given that the quality of mother-pup interactions has been demonstrated to affect pup[apos]s behaviour in adulthood, it may be that observed differences in spatial cognition and anxiety in febrilely convulsed pups are partially attributable to altered parenting.
[Supported by: CIHR; Heart and Stroke Foundation; NSERC]