Volitional control of parieto-occipital alpha lateralization via neurofeedback does not influence auditory spatial attention

Auditory spatial attention, the ability to focus selectively on specific sounds while ignoring others, is crucial for everyday listening. Lateralized alpha oscillations over the parieto-occipital cortex have been proposed to act as a crossmodal attentional filter mechanism that allows to gate sensory processing by actively suppressing unattended locations. While prior evidence supports the functional role of this mechanism in visual attention, its role in auditory spatial attention remains debated. In this pre-registered EEG-neurofeedback study, participants were trained for 30 minutes to lateralize alpha power toward the left or right parieto-occipital cortex, while auditory probes from different spatial directions (-90{degrees}, -45{degrees}, 45{degrees}, and 90{degrees}) assessed whether online changes in alpha lateralization influenced auditory processing. Resting-state and task-based alpha lateralization, as well as gaze behavior were measured before and after training. Participants successfully modulated alpha lateralization in the trained direction during neurofeedback. However, shifting alpha lateralization did not cause changes in online auditory processing, as evidenced by the absence of asymmetric changes in auditory evoked responses to lateralized probe tones. Likewise, neurofeedback did not cause persistent changes in alpha lateralization during resting-state and task-based recordings after neurofeedback. Notably, neurofeedback training affected gaze behavior. Shifting alpha lateralization toward the left hemisphere during neurofeedback abolished a pre-existing rightward gaze bias in training responders, pointing to a dissociation between oculomotor and auditory attentional systems. These findings challenge the notion that parieto-occipital alpha lateralization serves as a universal crossmodal spatial gate, and raise important questions about the functional specificity of alpha-based neurofeedback interventions.