Alpha-Band Phase Synchrony Is Related to Activity in the Fronto-Parietal Adaptive Control Network

Abstract

Neural oscillations in the α-band (8-12Hz) are increasingly viewed as an active inhibitory mechanism that gates and controls sensory information processing as a function of cognitive relevance. Extending this view, phase-synchronization of α-oscillations across distant cortical regions could regulate integration of information. Here, we investigated whether such long-range cross-region coupling in the α-band is intrinsically and selectively linked to activity in a distinct functionally specialized brain network. If so, this would provide new insight into the functional role of α-band phase-synchrony. We adapted the phase-locking value (PLV) to assess fluctuations in synchrony that occur over time in ongoing activity. Concurrent electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) were recorded during resting wakefulness in 26 human subjects. Fluctuations in global synchrony in the upper α-band correlated positively with activity in several prefrontal and parietal regions (as measured by fMRI). fMRI intrinsic connectivity analysis confirmed that these regions correspond to the well-known fronto-parietal (FP) network. Spectral correlations with this network’s activity confirmed that no other frequency band showed equivalent results. This selective association supports an intrinsic relation between large-scale α phase-synchrony and cognitive functions associated with the FP network. This network has been suggested to implement phasic aspects of top-down modulation such as initiation and change in moment-to-moment control. Mechanistically, long-range upper α-band synchrony is well-suited to support these functions. Complementing our previous findings that related α-oscillation power to neural structures serving tonic control, the current findings link α phase-synchrony to neural structures underpinning phasic control of alertness and task requirements.

Oscillations in the human brain during walking execution, imagination and observation

“…This suggests that the presence of alpha ERS burst may represent a 'windshield wiper' [76] effect through pulsed inhibition in order to update incoming information during walking. The rhythmic shift toward beta range during the walking imagery period can be discussed in relation to the fact that motor and somatosensory cortical areas are known to generate beta oscillation [77,78] and to modulate it in relation to motor execution, motor imagery and somatosensory stimulation [79][80][81][82].…”

Disrupted Functional Brain Networks in Autistic Toddlers

“…studies (Hillebrand et al, 2012;Sadaghiani et al, 2012). However, the association between development of cognitive functions and development of synchronization patterns in different frequency bands in children is not well understood yet.…”

Multi-dimensional modulations of α and γ cortical dynamics following mindfulness-based cognitive therapy in Major Depressive Disorder

“…Mean power for the early epoch (0-400 ms) and late epoch (400-800 ms) were then calculated, whereby FCz and Pz sites were used in the subsequent statistical analyses. These sites correspond to the fronto-parietal network, implicated in the top-down and bottom-up processing of moment-tomoment control/allocation of specialised functions (Sadaghiani et al 2012;Sauseng et al 2005;Wang et al 2010). Moreover, MDD has shown altered activity within this fronto-parietal loop (Jaworska et al 2012;Kemp et al 2010;Ricardo-Garcell et al 2009;Bauer and Hesselbrock 2002).…”

“…Moreover, enhanced long-range fronto-parietal coherence was exclusive to the α-band, whereby increased α-coherence has been linked to fluid complex higher-order functions, such as central executive control (Sauseng et al 2005: also specific to the fronto-parietal network), observational learning (van der Helden et al 2010), creativity (Orme-Johnson and Haynes 1981), and transcendental experience (Dillbeck and Bronson 1981). Furthermore, α-synchrony across distant fronto-parietal projections regulates the integration of information within the 'adaptive control network'; a top-down system implemented in the moment-to-moment control and allocation of sensory resources and specialised processing (Sadaghiani et al 2012). Related findings show enhanced right-intra-hemispheric coherence over fronto-temporal low frequency bands, i.e.…”