Gamma oscillations, observed in various brain regions during both waking and sleep states, are crucial for understanding neuronal population dynamics. The mechanisms underlying gamma oscillations involve perisomatic inhibition, which is essential for rhythmogenesis. Gamma oscillations are short-lived and emerge from the coordinated interaction of excitation and inhibition, detectable as local field potentials (LFPs). These oscillations often coincide with irregular firing of single neurons, and their frequency varies widely depending on the underlying mechanisms. To study gamma oscillations, it is important to distinguish them from mere increases in gamma-band power or spiking activity. The magnitude of gamma oscillations is modulated by slower rhythms, and cross-frequency coupling may facilitate the coordination of active cortical circuits. Gamma oscillations are widespread and strongly correlated with the operational modes of local circuits, providing valuable insights into neuronal population dynamics in health and disease.Gamma oscillations, observed in various brain regions during both waking and sleep states, are crucial for understanding neuronal population dynamics. The mechanisms underlying gamma oscillations involve perisomatic inhibition, which is essential for rhythmogenesis. Gamma oscillations are short-lived and emerge from the coordinated interaction of excitation and inhibition, detectable as local field potentials (LFPs). These oscillations often coincide with irregular firing of single neurons, and their frequency varies widely depending on the underlying mechanisms. To study gamma oscillations, it is important to distinguish them from mere increases in gamma-band power or spiking activity. The magnitude of gamma oscillations is modulated by slower rhythms, and cross-frequency coupling may facilitate the coordination of active cortical circuits. Gamma oscillations are widespread and strongly correlated with the operational modes of local circuits, providing valuable insights into neuronal population dynamics in health and disease.