Magnetic recordings from five normal human adults show large, coherent 40-Hz magnetic activity in both awake and rapid-eye-movement (REM) sleep states, which is significantly reduced during delta sleep. This 40-Hz oscillation is reset by sensory stimuli in the awake state but not during REM or delta sleep. The 40-Hz oscillation in both awake and REM sleep states is characterized by a fronto-occipital phase shift, with a maximum duration of approximately 12–13 milliseconds. The authors propose that this 40-Hz oscillation is a correlate of cognition, likely resulting from coherent 40-Hz resonance between thalamocortical-specific and nonspecific loops. The specific loops provide the content of cognition, while the nonspecific loop provides the temporal binding required for the unity of cognitive experience. The study used magnetoencephalography (MEG), a technique with high temporal resolution, to record brain activity. The results showed that 40-Hz activity occurs in an organized fashion during the dreaming state, with a rostrocaudal phase shift. The 40-Hz oscillation is prevalent in the activated mammalian central nervous system and is present at the single-cell level and at the multicellular and extracellular-field-potential levels. It is viewed as a possible mechanism for the conjunction of spatially distributed visual sensory activity. The study also found that 40-Hz oscillation is not reset by sensory input during delta and REM sleep, indicating a difference between these states and the awake state. The 40-Hz oscillation during REM sleep is similar to that in the awake state, but the lack of sensory reset suggests that the intrinsic activity of the nervous system is not influenced by external stimuli during dreaming. This supports the idea that the dream state is characterized by an increased attentiveness to an intrinsic state, with external stimuli not perturbing the intrinsic activity. The study also addressed the issue of the front-to-back phase shift of 40-Hz activity during REM sleep, showing a well-organized 12-millisecond phase shift. The results indicate that the 40-Hz oscillation is active during wakefulness and REM sleep, with similar global properties. The findings suggest that the 40-Hz oscillation is a key component of consciousness, involving both thalamocortical-specific and nonspecific loops. The specific system provides the content of cognition, while the nonspecific system provides the temporal binding required for the unity of cognitive experience.Magnetic recordings from five normal human adults show large, coherent 40-Hz magnetic activity in both awake and rapid-eye-movement (REM) sleep states, which is significantly reduced during delta sleep. This 40-Hz oscillation is reset by sensory stimuli in the awake state but not during REM or delta sleep. The 40-Hz oscillation in both awake and REM sleep states is characterized by a fronto-occipital phase shift, with a maximum duration of approximately 12–13 milliseconds. The authors propose that this 40-Hz oscillation is a correlate of cognition, likely resulting from coherent 40-Hz resonance between thalamocortical-specific and nonspecific loops. The specific loops provide the content of cognition, while the nonspecific loop provides the temporal binding required for the unity of cognitive experience. The study used magnetoencephalography (MEG), a technique with high temporal resolution, to record brain activity. The results showed that 40-Hz activity occurs in an organized fashion during the dreaming state, with a rostrocaudal phase shift. The 40-Hz oscillation is prevalent in the activated mammalian central nervous system and is present at the single-cell level and at the multicellular and extracellular-field-potential levels. It is viewed as a possible mechanism for the conjunction of spatially distributed visual sensory activity. The study also found that 40-Hz oscillation is not reset by sensory input during delta and REM sleep, indicating a difference between these states and the awake state. The 40-Hz oscillation during REM sleep is similar to that in the awake state, but the lack of sensory reset suggests that the intrinsic activity of the nervous system is not influenced by external stimuli during dreaming. This supports the idea that the dream state is characterized by an increased attentiveness to an intrinsic state, with external stimuli not perturbing the intrinsic activity. The study also addressed the issue of the front-to-back phase shift of 40-Hz activity during REM sleep, showing a well-organized 12-millisecond phase shift. The results indicate that the 40-Hz oscillation is active during wakefulness and REM sleep, with similar global properties. The findings suggest that the 40-Hz oscillation is a key component of consciousness, involving both thalamocortical-specific and nonspecific loops. The specific system provides the content of cognition, while the nonspecific system provides the temporal binding required for the unity of cognitive experience.