Intrinsic covariation of brain activity has been studied across many levels of brain organization. Between visual areas, neuronal activity covaries primarily among portions with similar retinotopic selectivity. We hypothesized that spontaneous interareal coactivation is subserved by neuronal synchronization. We performed simultaneous high-density electrocorticographic recordings across the dorsal aspect of several visual areas in one hemisphere in each of two awake monkeys to investigate spatial patterns of local and interareal synchronization. We show that stimulation-induced patterns of interareal coactivation were reactivated in the absence of stimulation for the visual quadrant covered. Reactivation occurred through both interareal cofluctuation of local activity and interareal phase synchronization. Furthermore, the trial-by-trial covariance of the induced responses recapitulated the pattern of interareal coupling observed during stimulation, i.e., the signal correlation. Reactivation-related synchronization showed distinct peaks in the theta, alpha, and gamma frequency bands. During passive states, this rhythmic reactivation was augmented by specific patterns of arrhythmic correspondence. These results suggest that networks of intrinsic covariation observed at multiple levels and with several recording techniques are related to synchronization and that behavioral state may affect the structure of intrinsic dynamics.vision | intrinsic activity | oscillations | connectivity | networks A classical approach to perceptual neuroscience suggests that the brain should respond identically to repetitions of identical stimuli. In this framework, endogenously driven variance in the brain's response to repeated stimuli is considered noise (1). However, this so-called noise has been found to be highly structured and influenced by behavioral context (2). In fact, such variation is a flavor of the ongoing, spontaneous activity of the brain. Both the variation in the brain's response to identical stimuli and its spontaneous activity in the absence of stimulation are endogenously generated and structured in spatially specific intrinsic networks. Highly specific intrinsic networks have been described at essentially all spatial scales: from two individual neurons up to the whole brain. Membrane potentials of nearby neurons show a high degree of spontaneous correlation (3). Neuronal spike rates cofluctuate across physically identical trials, and this socalled noise correlation between neurons is related to the similarity in their stimulus selectivity (4). Correspondingly, when entire maps of population activity are investigated, patterns of activation induced by stimuli are found to reoccur spontaneously (5). The same holds across neighboring maps in auditory cortex, where population activity spontaneously reproduces the tonotopic organization (6). Such coactivations can also be observed with functional MRI (fMRI). In visual cortex, regions selective for either foveal or peripheral stimuli, show correlated blood-oxygen level-d...