Sleep EEG changes after middle cerebral artery infarcts in mice: different effects of striatal and cortical lesions.
OBJECTIVE
Hemispheric stroke in humans is associated with sleep-wake disturbances and sleep electroencephalogram (EEG) changes. The correlation between these changes and stroke extent remains unclear. In the absence of experimental data, we assessed sleep EEG changes after focal cerebral ischemia of different extensions in mice.


METHODS
Following electrode implantation and baseline sleep-wake EEG recordings, mice were submitted to sham surgery (control group), 30 minutes of intraluminal middle cerebral artery (MCA) occlusion (striatal stroke), or distal MCA electrocoagulation (cortical stroke). One and 12 days after stroke, sleep-wake EEG recordings were repeated. The EEG recorded from the healthy hemisphere was analyzed visually and automatically (fast Fourier analysis) according to established criteria.


RESULTS
Striatal stroke induced an increase in non-rapid eye movement (NREM) sleep and a reduction of rapid eye movement sleep. These changes were detectable both during the light and the dark phase at day 1 and persisted until day 12 after stroke. Cortical stroke induced a less-marked increase in NREM sleep, which was present only at day 1 and during the dark phase. In cortical stroke, the increase in NREM sleep was associated in the wake EEG power spectra, with an increase in the theta and a reduction in the beta activity.


CONCLUSIONS
Cortical and striatal stroke lead to different sleep-wake EEG changes in mice, which probably reflect variable effects on sleep-promoting and wakefulness-maintaining neuronal networks.
Baumann
Christian R
CR
Department of Neurology, University Hospital Zurich, Zurich, Switzerland.
Kilic
Ertugrul
E
Petit
Brice
B
Werth
Esther
E
Hermann
Dirk M
DM
Tafti
Mehdi
M
Bassetti
Claudio L
CL
D000818:Animals; D002540:Cerebral Cortex / Q000473:pathology* / Q000503:physiopathology*; D003342:Corpus Striatum / Q000473:pathology* / Q000503:physiopathology*; D004195:Disease Models, Animal; D004569:Electroencephalography; D004576:Electromyography; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D020178:Sleep Disorders, Circadian Rhythm / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D012894:Sleep Stages / Q000502:physiology