Theta Oscillations Selectively Support Attentional Exploration of Space

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 reoriented between locations or between features, enabling attentional exploration. Sustained attention has long been associated with alpha (8-12 Hz) oscillations, whereas exploratory attention has been more recently proposed to rely on theta (4-7 Hz) oscillations. However, whether theta oscillations universally index exploration across spatial and nonspatial 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) poststimulus (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. Poststimulus 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.