Alpha oscillations support attentional orienting while beta supports perceptual decision-making.

Visuospatial attention enables the selective allocation of cognitive resources to relevant stimuli. A well-established neural signature of attentional shifts is the lateralised modulation of occipito-parietal alpha power, with decreases over the hemisphere contralateral to the attended location and increases over the ipsilateral hemisphere. However, growing evidence suggests that multiple oscillatory mechanisms contribute to attentional deployment, including beta-band activity. A key unresolved question that remains is whether the same neural rhythms support the deployment of attention and the perceptual decisions that follow. Here, we recorded EEG in 26 participants (22 females) during covert visuospatial orienting and investigated how alpha- and beta-band dynamics relate to behavioural measures, namely perceptual sensitivity (d') and decision criterion (c), and whether attended location could be preferentially decoded from alpha- or beta-band activity. We found that pre-target beta phase significantly predicted decision criterion at earlier pre-target intervals, whereas perceptual sensitivity was predicted closer to target onset, suggesting that beta is related to both sensory gain and the perceptual decision. In contrast, decoding analyses revealed that attended location was most strongly discriminable from alpha-band activity, as confirmed by time-frequency analysis of decoding accuracy. Together, these findings suggest a functional dissociation between oscillatory mechanisms supporting attentional orienting and perceptual decision-making. Whereas alpha-band activity primarily reflects the allocation of attention, beta-band dynamics predict trial-by-trial variability in perceptual decisions. Significance StatementAlthough alpha oscillations are commonly viewed as the principal neural mechanism underlying visuospatial attention, mounting evidence shows that such a complex function requires the involvement of other brain rhythms. Our findings show that different components of attention are associated with distinct brain rhythms. While alpha activity primarily reflects where attention is allocated, beta oscillations relate to how sensory information is transformed into perceptual decisions. These results suggest that attentional orienting and perceptual decision-making rely on dissociable neural processes, providing a comprehensive account of how brain oscillations support goal-directed behaviour.