Journal Article

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

Ikkai, Akiko, Curtis, Clayton E., Dandekar, Sangita

2016

Overview

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.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adult / Alpha Rhythm - physiology / Attention - physiology / Attention task / Biology and Life Sciences / Brain Mapping - methods / Competition / Cortex (frontal) / Cortex (occipital) / Cues / Data processing / Excitability / Female / Frontal Lobe - physiology / Functional Laterality - physiology / Humans / Information processing / Loci / Magnetoencephalography / Male / Medicine and Health Sciences / Memory / Neurons / NMR / Nuclear magnetic resonance / Occipital lobe / Occipital Lobe - physiology / Oscillations / Photic Stimulation - methods / Research and Analysis Methods / Saccadic eye movements / Sensors / Social Sciences / Space Perception - physiology / Spatial data / Spatial distribution / Studies / Synchronism / Synchronization / Topography / Visual cortex / Visual Cortex - physiology / Visual discrimination / Visual field / Visual fields / Visual Fields - physiology / Visual perception / Visual Perception - physiology / Visual stimuli / Visual task performance / Visual tasks / Young Adult