Characterization of the sleep–wake cycle of the Neotropical rodent

Abstract

Objectives: To better understand the sleep–wake cycle characteristics in the female Neotropical rodent Proechimys guyannensis related to comparative neurobiology. Methods: Surface neocortical and hippocampal electrodes were chronically implanted in the brains of female Wistar and Proechimys animals. In addition, electrodes for the study of muscle activity were implanted into the neck muscle of both species. After surgical recovery and a period of adaptation, animals were continuously registered for periods as long as 48 h. Results: In both the light and dark phases of the cycle, significant differences in some electrographic patterns were observed between the Proechimys and Wistar animals. Although Proechimys has nocturnal activities and a pattern of polyphasic sleep similar to Wistar rats, the analysis of its sleep-wakefulness cycle indicates that the Neotropical rodent sleeps less with consequent longer periods of wakefulness when compared to Wistar rats. Conclusions: Together with previous findings of different neuroanatomical, neurophysiologic and behavioral characteristics, this study allow us to better understand adaptive differences of the Neotropical rodent Proechimys.