Different coupling modes mediate cortical cross-frequency interactions

Abstract

Cross-frequency coupling (CFC) has been suggested to constitute a highly flexible mechanism for cortical information gating and processing, giving rise to conscious perception and various higher cognitive functions in humans. In particular, it might provide an elegant tool for information integration across several spatiotemporal scales within nested or coupled neuronal networks. However, it is currently unknown whether low-frequency (theta/alpha) or high-frequency gamma oscillations orchestrate cross-frequency interactions, raising the question of who is master and who is slave. While correlative evidence suggested that at least two distinct CFC modes exist, namely, phase-amplitude-coupling (PAC) and amplitude-envelope correlations (AEC), it is currently unknown whether they subserve distinct cortical functions. Novel non-invasive brain stimulation tools, such as transcranial alternating current stimulation (tACS), now provide the unique opportunity to selectively entrain the low- or high-frequency component and study subsequent effects on CFC. Here, we demonstrate the differential modulation of CFC during selective entrainment of alpha or gamma oscillations. Our results reveal that entrainment of the low-frequency component increased PAC, where gamma power became preferentially locked to the trough of the alpha oscillation, while gamma-band entrainment enhanced AECs and reduced alpha power. These results provide causal evidence for the functional role of coupled alpha and gamma oscillations for visual processing.

Oscillatory Dynamics of Prefrontal Cognitive Control

“…Notably, there is an ongoing debate about whether the low frequency phase drives the amplitude of the high frequency component or vice versa [77]. It has been suggested that both components could drive the interaction to facilitate information integration across temporal scales [78], but it is unclear how directional synchrony across several spatiotemporal scales is established.…”

“…Furthermore, amplitude correlations [57,60] might exhibit similar characteristics and could be applied to both connectivity and CFC analyses [78] and could serve as a useful control analysis [60]. The mutual information framework provides a promising approach to capture non-linear dependencies in electrophysiological data 2 ([122], Figure Id), which cannot be described by linear correlation analyses.…”

Gap Junction Modulation of Low-Frequency Oscillations in the Cerebellar Granule Cell Layer

“…Local field potential (LFP) oscillations in local networks result from the synchronization of neuronal activity, and the synchrony of oscillations from separate areas of the brain may contribute to the temporal binding of information [3][4][5][6][7]. Synchronous oscillations in sensorimotor areas reflect coordinated firing of activity across regions and may contribute to optimally planned and executed movements [8][9][10].…”

“…The cerebellum plays a pivotal role in many aspects of sensorimotor processing and displays low-frequency LFP oscillations that are synchronized with those in primary somatosensory cortex and motor areas [11][12][13][14]. Low-frequency cerebellar oscillations have been recorded in the granule cell layer (GCL) of awake and alert rodents (7)(8) and primates (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) [12,[15][16][17], and are present both at rest and during preparation for movement [12,14,[16][17][18]. In addition, single and multi-unit firing activity within the GCL is phase-locked with GCL oscillations [15][16][17].…”

Transcranial electric stimulation (tES) and NeuroImaging: the state-of-the-art, new insights and prospects in basic and clinical neuroscience

“…They found that entrainment of the low-frequency component increased phaseamplitude-coupling (PAC), where gamma power became preferentially locked to the 'trough' or 'down-phase' of the alpha oscillation, while gamma-band entrainment enhanced amplitude-envelope correlations (AECs) and reduced alpha power (Helfrich et al, 2016). …”