Paradoxical sleep is characterized by uncoupled gamma activity between frontal and perceptual cortical regions

Study Objectives: Coherent activity of fast activity has been postulated to be a common language of the brain involved in the processing of informatio n and in integration of spatially separated but temporally correlated stimu li into whole events. Any disruption affecting temporality would result in distortion of cognitive activity. Dreaming during paradoxical sleep (PS) sh ows cognitive alterations that mimic frontal lobe dysfunction, Decreased te mporal coupling of EEG between frontal and perceptual regions was hypothesi zed. The main objective was to explore temporal relationships of fast activ ity among these regions. Design: N/A Setting: N/A Participants: 8 young adults, Interventions: N/A Measurements and Results: Interhemispheric (INTERr) and intrahemispheric (I NTRAr) EEG correlation spectra (1-50 Hz) were obtained for wakefulness, sta ge 2, stage 4, and PS during the second night spent at the laboratory. INTE Rr showed a significant overall increase during sleep in comparison to wake fulness, whereas INTRAr of fast activity (27-48 Hz) between frontal-percept ual regions (F-P, F-O, F-T, FpP, Fp-T) decreased exclusively during PS whil e INTRAr among perceptual regions (P-O, P-T, O-T) maintained wakefulness va lues. Conclusions: Present results demonstrate state- and frequency-dependent shi fts on temporal coupling. The hypothesized decrease in correlation of fast activity between frontal and perceptual regions during PS was confirmed, Th is decrease of temporal coupling might underlie the lass of voluntary direc tion of thinking and congruence with social and temporal context and the la ck of judgment and passive acceptance of bizarreness during PS dreaming. Th e wakefulness levels in correlation of fast activity among perceptual regio ns might explain perceptual acuity during PS dreaming.