AUTHOR=Grønli Janne , Schmidt Michelle A. , Wisor Jonathan P. 

TITLE=State-Dependent Modulation of Visual Evoked Potentials in a Rodent Genetic Model of Electroencephalographic Instability

JOURNAL=Frontiers in Systems Neuroscience

VOLUME=12

YEAR=2018

URL=https://www.frontiersin.org/journals/systems-neuroscience/articles/10.3389/fnsys.2018.00036

DOI=10.3389/fnsys.2018.00036

ISSN=1662-5137

ABSTRACT=<p>Despite normal sleep timing and duration, <italic>Egr3</italic>-deficient (<italic>Egr3</italic><sup>−/−</sup>) mice exhibit electroencephalographic (EEG) characteristics of reduced arousal, including elevated slow wave (1–4 Hz) activity during wakefulness. Here we show that these mice exhibit state-dependent instability in the EEG. Intermittent surges in EEG power were found in <italic>Egr3</italic><sup>−/−</sup> mice during wakefulness and rapid eye movement sleep, most prominently in the beta (15–35 Hz) range compared to wild type (<italic>Egr3</italic><sup>+/+</sup>) mice. Such surges did not coincide with sleep onset, as the surges were not associated with cessation of electromyographic tone. Cortical processing of sensory information by visual evoked responses (VEP) were found to vary as a function of vigilance state, being of higher magnitude during slow wave sleep (SWS) than wakefulness and rapid eye movement sleep. VEP responses were significantly larger during quiet wakefulness than active wakefulness, in both <italic>Egr3</italic><sup>−/−</sup> mice and <italic>Egr3</italic><sup>+/+</sup> mice. EEG synchronization in the beta range, previously linked to the accumulation of sleep need over time, predicted VEP magnitude. <italic>Egr3</italic><sup>−/−</sup> mice not only displayed elevated beta activity, but in quiet wake, this elevated beta activity coincides with an elevated evoked response similar to that of animals in SWS. These data confirm that (a) VEPs vary as a function of vigilance state, and (b) beta activity in the EEG is a predictor of state-dependent modulation of visual information processing. The phenotype of <italic>Egr3</italic><sup>−/−</sup> mice indicates that <italic>Egr3</italic> is a genetic regulator of these phenomena.</p>