Sleepwalking episodes are preceded by arousal-related activation in the cingulate motor area: EEG current density imaging

EEG Functional Connectivity Prior to Sleepwalking: Evidence of Interplay Between Sleep and Wakefulness

“…This suggests that the coexistence of sleep and wakefulness is not only present during the episodes themselves, but also prior to their behavioral onset. This line of reasoning is also consistent with recent findings suggesting the coexistence of wake-related activity and deep sleep in adults with disorders of arousal, both immediately preceding the onset of behavioral episodes 19 as well as during whole-night sleep periods devoid of clinical events. 26 Since up to 90% of arousals occurring out of NREM sleep have been shown to be preceded by elevated delta activity, 42 many NREM sleep activation phenomena have been conceptualized as variants of the same process: an initial high-voltage slow-wave EEG activation reflecting the readiness of the cerebral cortex to shift towards stronger activating effects of rapid EEG rhythms.…”

“…18,19 The pre-episode increase in beta EEG connectivity found in our subjects involved symmetrical frontal-occipital networks which may be related to motor manifestations underlying somnambulistic episodes. Specifically, these fast activity connectivity networks were found to coexist with delta activity in associative brain areas, a result in line with findings in parasomniac patients suggesting the coexistence of slow activity in frontal areas and fast activity in motor areas both before 18 and during sleepwalking episodes.…”

“…Using stereo electroencephalography, Terzaghi and colleagues 18 reported a single case study in which beta activity (indicative of wakefulness) was recorded in the motor and central cingulate cortices 5 seconds before a sleepwalking episode along with increased delta bursts (indicative of sleep) in the frontal and parietal dorsolateral associative cortices. Similarly, using electromagnetic tomography (eLORETA) in 15 adult sleepwalkers, Januszko and colleagues 19 reported a significant activation in the 24-30 Hz beta frequency range 4 seconds prior to the onset of somnambulistic episodes. Taken together, these findings indicate that changes in sleep EEG are observed prior to the onset of behavioral episodes and suggest that sleepwalking is characterized by a state reflecting the interplay between the states of deep sleep and wakefulness.…”

“…These symmetrical interhemispheric networks may be related to brain regions previously described as showing increased activity in association with NREM parasomnias. These areas include the motor cortex, 18,51 cingulate, 18,19,50,51 insular, amygdalar and temporopolar cortices, 51 as well as the anterior cerebellum. 50 Taken together, these results suggest beta functional connectivity networks may be related to brain activity in motor, cingulate and temporopolar areas and may constitute an early manifestation of somnambulistic episodes.…”

Adult NREM Parasomnias: An Update

“…Furthermore, there was an increase in delta activity, typical of N3 sleep, in frontoparietal associative cortices. Supporting lines of evidence came from another EEG study, which utilised low resolution electromagnetic tomography to show increased current density in beta bands in the cingulate motor area immediately prior to an episode of sleepwalking [41]. The enhancement of N3 sleep in the frontoparietal areas, versus the wake-like activation of motor and cingulate cortices suggests dissociation between the states of wake and sleep.…”