The article by Harris and Thiele explores the dynamics of cortical state and its impact on attention and sensory processing. Cortical states, characterized by low-frequency activity fluctuations and spiking correlation, are modulated by external stimuli and endogenous patterns. The authors discuss two experimental approaches: state-dependent cortical processing in rodents and attention in primate visual systems. They argue that attention involves processes similar to state change, operating at a local columnar level to enhance the representation of nonsalient features while suppressing internally generated activity patterns. Cortical states are not bimodal but form a continuum, varying within wakefulness and influenced by different behavioral and experimental conditions. The authors highlight the role of neuromodulatory systems and tonic glutamatergic drive in controlling cortical states, particularly in maintaining desynchronized states and causing fluctuations in synchronized states. They also discuss the complex relationship between cortical state and sensory responses, suggesting that sudden, punctate stimuli are more effectively processed in both synchronized and desynchronized states, while temporally extended stimuli are better represented in desynchronized states. In primates, attention is shown to modulate local desynchronization, reducing low-frequency power and trial-to-trial variability in attended areas. The circuit mechanisms underlying these effects involve cholinergic and glutamatergic systems, with glutamatergic feedback projections playing a crucial role in increasing the gain of visual cortical responses. The authors conclude that cortical state is a multidimensional continuum, and future research using advanced techniques like optogenetics and enzyme-linked electrochemistry may reveal how multiple neuromodulatory systems shift cortical operating modes. They also suggest that synchronized states may serve as a "power save" mode or a signature of non-sensory information processing.The article by Harris and Thiele explores the dynamics of cortical state and its impact on attention and sensory processing. Cortical states, characterized by low-frequency activity fluctuations and spiking correlation, are modulated by external stimuli and endogenous patterns. The authors discuss two experimental approaches: state-dependent cortical processing in rodents and attention in primate visual systems. They argue that attention involves processes similar to state change, operating at a local columnar level to enhance the representation of nonsalient features while suppressing internally generated activity patterns. Cortical states are not bimodal but form a continuum, varying within wakefulness and influenced by different behavioral and experimental conditions. The authors highlight the role of neuromodulatory systems and tonic glutamatergic drive in controlling cortical states, particularly in maintaining desynchronized states and causing fluctuations in synchronized states. They also discuss the complex relationship between cortical state and sensory responses, suggesting that sudden, punctate stimuli are more effectively processed in both synchronized and desynchronized states, while temporally extended stimuli are better represented in desynchronized states. In primates, attention is shown to modulate local desynchronization, reducing low-frequency power and trial-to-trial variability in attended areas. The circuit mechanisms underlying these effects involve cholinergic and glutamatergic systems, with glutamatergic feedback projections playing a crucial role in increasing the gain of visual cortical responses. The authors conclude that cortical state is a multidimensional continuum, and future research using advanced techniques like optogenetics and enzyme-linked electrochemistry may reveal how multiple neuromodulatory systems shift cortical operating modes. They also suggest that synchronized states may serve as a "power save" mode or a signature of non-sensory information processing.