Lateralization in Alpha-Band Oscillations Predicts the Locus and Spatial Distribution of Attention

Abstract

Attending to a task-relevant location changes how neural activity oscillates in the alpha band (8–13Hz) in posterior visual cortical areas. However, a clear understanding of the relationships between top-down attention, changes in alpha oscillations in visual cortex, and attention performance are still poorly understood. Here, we tested the degree to which the posterior alpha power tracked the locus of attention, the distribution of attention, and how well the topography of alpha could predict the locus of attention. We recorded magnetoencephalographic (MEG) data while subjects performed an attention demanding visual discrimination task that dissociated the direction of attention from the direction of a saccade to indicate choice. On some trials, an endogenous cue predicted the target’s location, while on others it contained no spatial information. When the target’s location was cued, alpha power decreased in sensors over occipital cortex contralateral to the attended visual field. When the cue did not predict the target’s location, alpha power again decreased in sensors over occipital cortex, but bilaterally, and increased in sensors over frontal cortex. Thus, the distribution and the topography of alpha reliably indicated the locus of covert attention. Together, these results suggest that alpha synchronization reflects changes in the excitability of populations of neurons whose receptive fields match the locus of attention. This is consistent with the hypothesis that alpha oscillations reflect the neural mechanisms by which top-down control of attention biases information processing and modulate the activity of neurons in visual cortex.

Topographic specificity of alpha power during auditory spatial attention

“…The pattern of alpha lateralization that we report is consistent with the theory that alpha reflects a 472 alpha-linked suppression of information in subnetworks of the brain representing other retinotopic 480 locations. Our observation of a gradation of parietal alpha power lateralization that reflects the 481 exact attentional focus is consistent with the theory that local alpha power modulation "reflects 482 changes in the excitability of populations of neurons whose receptive fields match the locus of 483 attention" (Ikkai et al, 2016;Klimesch, 2012). 484…”

“…Specifically, in the parietal lobe ipsilateral to the direction of attention, alpha increases to suppress 48 objects that are to be ignored, while in the parietal lobe contralateral to the direction of attention, 49 alpha decreases to allow processing of an attended object (Ikkai et al, 2016). 50…”

Unraveling the relation between EEG-correlates of attentional orienting and sound localization performance: a diffusion model approach

“…Typically, alpha lateralization manifests in a bilateral decrease of alpha power, that is more pronounced over the contralateral hemisphere (relative to a target or a cue). This spatially specific modulation of oscillatory activity has been repeatedly associated with the top-down controlled voluntary allocation of attention (Foxe, Simpson, & Ahlfors, 1998;Haegens et al, 2011;Ikkai et al, 2016;Thut et al, 2006). Here, we replicated this consistently observed response in the alpha frequency band in a sample of younger and older participants who performed an auditory localization task, requiring them to indicate the location of a pre-defined target stimulus among three concordantly presented distractors.…”

“…Lateralized modulations of alpha power amplitude have been shown to reflect the orienting of spatial attention in visual (Foster, Sutterer, Serences, Vogel, & Awh, 2017;Ikkai, Dandekar, & Curtis, 2016;Rihs, Michel, & Thut, 2007;Worden, Foxe, Wang, & Simpson, 2000), tactile (Haegens, Handel, & Jensen, 2011;Haegens, Luther, & Jensen, 2012), and auditory space (Klatt, Getzmann, Wascher, & Schneider, 2018b;Wöstmann, Herrmann, Maess, & Obleser, 2016;Wöstmann, Vosskuhl, Obleser, & Herrmann, 2018). Typically, alpha power is shown to decrease contralaterally to the attended location (Kelly, Gomez-Ramirez, & Foxe, 2009;Sauseng et al, 2005) or to increase contralaterally to the unattended or ignored location (Kelly, Lalor, Reilly, & Foxe, 2006;Worden et al, 2000).…”

Dynamics of cognitive control: Theoretical bases, paradigms, and a view for the future

“…Blocking of alpha band activity is a common signature of working memory encoding for future retrieval (Jensen, Gelfand, Kounios, & Lisman, ; Klimesch et al, ; Sauseng et al, ). Selective attention and proactive inhibition are associated with changes in alpha power over posterior sites (e.g., Foxe & Snyder, ; Fu et al, ; Hanslmayr, Gross, Klimesch, & Shapiro, ; Ikkai, Dandekar, & Curtis, ). Moreover, activity in posterior alpha (Foxe, Murphy, & De Sanctis, ; Mansfield, Karayanidis, & Cohen, ), theta (Cooper et al, ; Cunillera et al, ; Sauseng et al, ), and central beta (Gladwin, Lindsen, & de Jong, ) has been linked to advance preparation for switching tasks in task‐switching paradigms.…”