Novel object presentation affects sleep-wake behavior in rats

Sleep is suggested to be crucial for the processing and storage of new informations. The enhancement of both, spindle activity within NREM (non-rapid eye movement sleep) and theta activity within REM is suggested to serve as background activity for the synchronization of those neuronal pathways, that were involved in the registration and, later on, participate in the long term storage of new informations in defined brain regions. In the present study, the presentation of a novel object to rats enhanced the amount of preREMS, an intermediate sleep stage with high spindle activity, within the first 2 hours of the subsequent sleeping phase. Four hours later, the amount of REMS was increased, as well. There were no changes in the EEG power spectra of nonREMS, preREMS and REMS. The increase of preREMS and REMS amounts and the related spindle and theta activity are suggested to stand for the processing and storage of new informations about the presented novel objects.