Brain Networks and α-Oscillations: Structural and Functional Foundations of Cognitive Control

The α-rhythm causes cyclic inhibition and thereby modulates neural excitability. Cross-frequency coupling is observed between α phase and the power of high-frequency (γ) population activity. The functional impact of α power, phase, and long-range phase synchrony are dissociable. The α-rhythm is actively deployed to serve cognitive processes, and α-oscillations can be modulated by top-down functions. The functional role of the α-rhythm is comparable across different sensory modalities (visual, auditory, somatosensory) and the motor system. Spontaneous variations in α-band power and phase synchrony are related to activity fluctuations in large-scale functional networks (multimodal imaging). Large-scale cognitive control networks may top-down modulate α-oscillations to influence neural excitability and information flow. The most salient electrical signal measured from the human brain is the α-rhythm, neural activity oscillating at ∼100 ms intervals. Recent findings challenge the longstanding dogma of α-band oscillations as the signature of a passively idling brain state but diverge in terms of interpretation. Despite firm correlations with behavior, the mechanistic role of the α-rhythm in brain function remains debated. We suggest that three large-scale brain networks involved in different facets of top-down cognitive control differentially modulate α-oscillations, ranging from power within and synchrony between brain regions. Thereby, these networks selectively influence local signal processing, widespread information exchange, and ultimately perception and behavior. The most salient electrical signal measured from the human brain is the α-rhythm, neural activity oscillating at ∼100 ms intervals. Recent findings challenge the longstanding dogma of α-band oscillations as the signature of a passively idling brain state but diverge in terms of interpretation. Despite firm correlations with behavior, the mechanistic role of the α-rhythm in brain function remains debated. We suggest that three large-scale brain networks involved in different facets of top-down cognitive control differentially modulate α-oscillations, ranging from power within and synchrony between brain regions. Thereby, these networks selectively influence local signal processing, widespread information exchange, and ultimately perception and behavior. an umbrella term for a group of regulatory functions that modulate information processing and information flow so as to map sensory inputs, internal states, and behavioral outputs according to goals. a (usually) noninvasive method to measure electrical brain signals most commonly from the scalp. These signals are thought to originate primarily from apical dendrites of radially oriented pyramidal neurons whose population activity is sufficiently strong to be measured at the scalp. the readiness of a neural population to fire action potentials in response to excitatory input. On the fast timescales referred to in the context of oscillations and fast cognitive processes, the excitability of a neuron is changed by excitatory and inhibitory synaptic inputs influencing its membrane potential. statistical dependencies among remote neurophysiological events, often inferred on the basis of correlations among measurements of neuronal activity. a noninvasive method to record brain activity with high spatial resolution (∼mm range) and whole-brain coverage. The recorded signal originates from changes in blood oxygenation levels following neural activity, and is thought to reflect postsynaptic potentials pooled across neural populations. the power of oscillatory activity from the cortex averaged over all EEG scalp electrodes. reduction in neural excitability. in electrophysiology, oscillations comprise neural ensemble activity that waxes and wanes periodically at a specific speed measured as cycles per second (Hz). In scalp and cortical surface measurements these oscillations are thought to reflect local field potentials. EEG oscillations are typically divided into δ (∼1–4 Hz), θ (∼4–8 Hz), α (∼8–12 Hz), β (∼12–30 Hz), γ (∼30–60 Hz), and high-γ (∼60–160 Hz) frequency bands. position along the wave cycle of an oscillatory signal, such as the peak or trough. The phase is determined for individual frequencies or frequency bands and reported as radians [−π, π] or degrees [−180, +180]. a measure of consistency of phase lags between two oscillatory signals. Note that the phase difference or lag and the amplitude of the two signals have no influence on this measure. PLV measures whether the lag between the instantaneous phases of the two signals is stable across many instances such as across trials or across timepoints. the power of an oscillatory signal at a particular frequency (in frequency domain) corresponds to the magnitude of that frequency present in the recorded signal timecourse (in time domain). It is typically reported in units of micro- or millivolts squared. the influence of brain areas in association cortices of parietal and frontal lobes on processing of sensory input and motor output signals in sensory and motor cortices reflecting a hierarchy of brain function.