Attention facilitates stimulus processing by selecting specific locations (spatial attention) or features (feature-based attention). It can be sustained on a given location or feature, or re-oriented between locations or between features, enabling attentional exploration. Sustained attention has long been associated with alpha (8-12Hz) oscillations, whereas exploratory attention has been more recently proposed to rely on theta (4-7Hz) oscillations. However, whether theta oscillations universally index exploration across spatial and non-spatial dimensions remains unclear as prior evidence stems from disparate paradigms and attentional manipulations. Here, we systematically examined attentional exploration of stimulus dimensions (location/feature) in human participants (male/female) using EEG and a cueing paradigm during the (1) precue-to-stimulus (first attentional orienting) and (2) post-stimulus (during stimulus processing) trial periods. In the precue-to-stimulus period, multivariate decoding revealed rhythmic modulations of neural information content: alpha-band rhythms emerged during sustained attention regardless of dimension, whereas theta-band rhythms were observed selectively when attention was sustained on features but required exploration of spatial locations. Post-stimulus analyses confirmed this link: theta power increased during invalid trials that required attentional reorienting relative to valid trials, and this effect predicted faster reaction times and higher accuracy. Together, these findings clarify the functional role of neural oscillations in attentional orienting and exploration, highlighting theta as a signature of spatial exploration rather than a domain-general mechanism. Significance statement Attention can be sustained on relevant sensory information or reoriented to explore new inputs. While alpha-band oscillations are known to accompany sustained attention, the role of theta-band oscillations has been debated. Using electroencephalography in humans, we show that theta activity specifically supports exploration across space rather than a general mechanism of attentional sampling. Theta oscillations increased when attention had to shift spatially and predicted subsequent behavioral performance. These findings demonstrate that theta activity is not a domain-general signature of attentional sampling but a mechanism supporting spatial exploration, refining our understanding of how distinct neural rhythms coordinate attentional orienting and reorienting.
Senoussi et al. (Thu,) studied this question.