Sleep/Wake Dynamics Changes during Maturation in Rats

Abstract

ObjectivesConventional scoring of sleep provides little information about the process of transitioning between vigilance states. We applied the state space technique (SST) using frequency band ratios to follow normal maturation of different sleep/wake states, velocities of movements, and transitions between states of juvenile (postnatal day 34, P34) and young adult rats (P71).Design24-h sleep recordings of eight P34 and nine P71 were analyzed using conventional scoring criteria and SST one week following implantation of telemetric transmitter. SST is a non-categorical approach that allows novel quantitative and unbiased examination of vigilance-states dynamics and state transitions. In this approach, behavioral changes are described in a 2-dimensional state space that is derived from spectral characteristics of the electroencephalography.Measurements and ResultsWith maturation sleep intensity declines, the duration of deep slow wave sleep (DSWS) and light slow wave sleep (LSWS) decreases and increases, respectively. Vigilance state determination, as a function of frequency, is not constant; there is a substantial shift to higher ratio 1 in all vigilance states except DSWS. Deep slow wave sleep decreases in adult relative to juvenile animals at all frequencies. P71 animals have 400% more trajectories from Wake to LSWS (p = 0.005) and vice versa (p = 0.005), and 100% more micro-arousals (p = 0.021), while trajectories from LSWS to DSWS (p = 0.047) and vice versa (p = 0.033) were reduced by 60%. In both juvenile and adult animals, no significant changes were found in sleep velocity at all regions of the 2-dimensional state space plot; suggesting that maturation has a partial effect on sleep stability.ConclusionsHere, we present novel and original evidence that SST enables visualization of vigilance-state intensity, transitions, and velocities that were not evident by traditional scoring methods. These observations provide new perspectives in sleep state dynamics and highlight the usefulness of this technique in exploring the development of sleep-wake activity.

The bioelectric type of the visual area of the cerebral cortex of rats of all ages and sexes

“…At this age, ECoG of rats acquires the importance of the frequency and amplitude characterristic of adult rats (Gao et al, 2015). However, there is evidence that this concept is not entirely true, and the differences in rhythms continue to change and mature after adolescence in animals and humans (Gradwohl et al, 2015).…”

Does experimental paradoxical sleep deprivation (EPSD) is an appropriate model for evaluation of cardiovascular complications of obstructive sleep apnea?

“…However, in animal literature, the terms SWS and non-REM sleep have been used interchangeably and considered to be the same stage of sleep [35]. In addition, it seems that the sleep/wake dynamics changes during maturation in rat and human fallow almost the similar pattern [36]. So, although the same with the other animal studies, the results of the present study is not fully applicable to human, but as a model can help to realize the mechanisms involved in sleep loss complications.…”

Methodologic recommendations and possible interpretations of video‐EEG recordings in immature rodents used as experimental controls: A TASK1‐WG2 report of the ILAE/AES Joint Translational Task Force

“…Adult rats have more microarousals and transitions between wake and light sleep, whereas P34 rats have fewer transitions from light SWS (delta with 6–15 Hz sleep spindles) to deep SWS (>70% delta slowing with reduced EMG and motor activity). Consequently, P71 rats spent more time in light SWS (26%) than P34 rats (17%) and less time in PS (7.6% vs. 11%, respectively) …”

“…The EEG was predominantly low‐amplitude delta with bursts of theta between P5 and 7 and progressively increased in frequencies and amplitude between P10 and 12 (alpha [8–12 Hz] background with theta bursts) until P25–27 . Although qualitatively the sleep‐wake EEG of P30 rodents resembles the adult EEG, some quantitative differences in sleep‐wake transitions have been observed between P34 and P71 rats . Adult rats have more microarousals and transitions between wake and light sleep, whereas P34 rats have fewer transitions from light SWS (delta with 6–15 Hz sleep spindles) to deep SWS (>70% delta slowing with reduced EMG and motor activity).…”