Spatial Attention and the Effects of Frontoparietal Alpha Band Stimulation

Abstract

A frontoparietal network has long been implicated in top-down control of attention. Recent studies have suggested that this network might communicate through coherence in the alpha band. Here we aimed to test the effect of coherent alpha (8–12 Hz) stimulation on the frontoparietal network. To this end, we recorded behavioral performance and electroencephalography (EEG) data while participants were engaged in a spatial attention task. Furthermore, participants received transcranial alternating current stimulation (tACS) over the right frontal and parietal cortex, which oscillated coherently in-phase within the alpha band. Compared to a group of participants that received sham stimulation, we found that coherent frontoparietal alpha band stimulation altered a behavioral spatial attention bias. Neurally, the groups showed hemispheric-specific differences in alpha coherence between the frontal and parietal-occipital cortex. These results provide preliminary evidence that alpha coherence in the frontoparietal network might play a role in top-down control of spatial attention.

Disruption of large-scale electrophysiological networks in stroke patients with visuospatial neglect

“…Remarkably, changes in alpha-band connections significantly correlated with the severity of visuospatial biases and implicated symmetrical regions over the extra-striate visual cortex (pericalcarine and lingual), where hypoconnectivity with the left-hemisphere predicted more left visual-field omissions, while the converse (hypoconnectivity with the right-hemisphere) was observed for right visual-field omissions. This topographically-specific dysconnection pattern is compatible with the role of alpha rhythms in contralateral visuospatial attention (Ikkai, Dandekar, and Curtis 2016;Lobier, Palva, and Palva 2017;van Schouwenburg, Zanto, and Gazzaley 2017), as well as previous studies on hemineglect utilizing functional Sasaki et al 2013) and structural (Karnath et al 2011;Vaessen et al 2016) neuroimaging to delineate the functional neuro-anatomy of visuospatial deficits. Moreover, it is interesting to note that while the alpha band was implicated in the dysconnectivity pattern of right TPJ with sensory visual areas, the beta band was distinctively involved in dysconnectivity with left prefrontal areas which presumably subserve more executive processes of attention (Antzoulatos and Miller 2016).…”

Novel bifunctional cap for simultaneous electroencephalography and transcranial electrical stimulation

“…These two aspects can reduce the time burden for patients and volunteers and allow the use of the cap without a trained medical staff. Third, the elimination of the need for skin preparation and electrolyte gel reduces the risk of skin irritations and hair loss, which constitutes an advantage of our cap over other caps 40 using gel-based Ag/AgCl electrodes for TES. A fourth benefit of the textile cap stimulation electrodes is that the stimulation electrode can be designed individually and thus areas and shapes are not restricted to the size of Ag/AgCl electrodes.…”

“… 39 and van Schouwenburg et al . 40 proposed combined TES–EEG caps incorporating conventional Ag/AgCl electrodes for both EEG and TES to overcome problems of positioning reproducibility. However, the main drawback of using conventional EEG electrodes for TES consists in the risk of exceeding the current density limit 10 of 80 µA/cm².…”

No Differential Effects of Two Different Alpha-Band Electrical Stimulation Protocols Over Fronto-Parietal Regions on Spatial Attention

“…In a recent study, we tested the hypothesis that the fronto-parietal network employs top–down control over visual regions through communication in the alpha band ( van Schouwenburg et al, 2017 ). Current theorizing suggests that brain regions communicate through neural coherence, such that when activity in two brain regions oscillates in phase, communication is increased, while communication is hampered when activity in brain regions oscillates out of phase ( Womelsdorf and Fries, 2007 ; Sauseng and Klimesch, 2008 ).…”

“… In a previous study using transcranial alternating current stimulation (tACS), we found preliminary evidence that phase coherence in the alpha band (8–12 Hz) within the fronto-parietal network may critically support top-down control of spatial attention ( van Schouwenburg et al, 2017 ). Specifically, synchronous alpha-band stimulation over the right frontal and parietal cortex (0° relative phase) was associated with changes in performance and fronto-parietal coherence during a spatial attention task as compared to sham stimulation.…”