Causal links between parietal alpha activity and spatial auditory attention

Abstract

1 Both visual and auditory spatial selective attention result in lateralized alpha (8-14 Hz) oscillatory 2 power in parietal cortex: alpha increases in the hemisphere ipsilateral to attentional focus. Brain 3 stimulation studies suggest a causal relationship between parietal alpha and suppression of the 4 representation of contralateral visual space. However, there is no evidence that parietal alpha 5 controls auditory spatial attention. Here, we performed high definition transcranial alternating 6 current stimulation (HD-tACS) on human subjects performing an auditory task in which they 7 attended either spatial or nonspatial features. Alpha (10 Hz) but not theta (6 Hz) HD-tACS of right 8 parietal cortex interfered with attending left but not right auditory space. Parietal stimulation had 9 no effect for nonspatial auditory attention. Moreover, performance in post-stimulation trials 10 returned rapidly to baseline. These results demonstrate a causal, frequency-, hemispheric-, and 11task-specific effect of parietal alpha brain stimulation on top-down control of auditory spatial 12 attention. 13 42 stimulus. The average of alpha power during a preparatory period (after an auditory cue indicating the 43 target position, but prior to the start of the sound presentation) is shown separately for left and right 44 parietal sensors in the left and right bottom panels, respectively. B). Adapted with permission from 13 . 45Disruption of alpha lateralization when spatial attention is disrupted by a discontinuity in the target talker. 46Example stimuli are shown at the top for trials in which the nonspatial (talker) features of two competing 47 speech streams are continuous (left) and when they switch, which, if it occurred, always was after the first 48 two target syllables (right). Topographies show the normalized difference in alpha power when listeners 49 focus attention to the left minus when they focus attention to the right (relative to the sum of the alpha power 50 for attend-left plus attend-right), computed separately at each sensor on the scalp. Averages are computed 51 from the moment of the potential talker switch to the end of the trial. The bottom bar graphs show the 52 average normalized alpha change over the posterior left and posterior right channels computed from the 53 scalp distributions. For switching trials, parietal alpha lateralization is weakened following the talker 54 change. 55 Talker discontinuity disrupts auditory spatial attention 56Numerous behavioral studies demonstrate that maintaining attention on an ongoing auditory 57 stream is supported by continuity of features like pitch, location, voice, and timbre 21,22 . Feature 58 continuity influences performance automatically: even when listeners know they should ignore 59 some feature, such as talker identity, and attend to a different feature, such as location, 60 discontinuities in the task-irrelevant feature disrupt attention 21,23,24 . Indeed, effects of talker 61 128 Figure 2. Task paradigm. A) Trial timeline. Subjects were instructed to...

Large-scale frontoparietal theta, alpha, and beta phase synchronization: A set of EEG differential characteristics for freezing of gait in Parkinson’s disease?

“…So, it is crucial to investigate the association between the phase features of ultra-slow cortical potentials and FOG. Moreover, lack of left 10.3389/fnagi.2022.988037 parietal low alpha phase synchrony at superficial layers might be related to the auditory cue during the movement task in the current protocol (Meyer et al, 2013;Deng et al, 2019). Further research should be undertaken to investigate the role of the phase of the left parietal low alpha frequency band in FOG.…”