Selective attention to auditory and visual modalities converges onto noncholinergic basal forebrain neurons

Selective attention enables animals and humans to prioritize behaviorally relevant stimuli among competing sensory inputs. Although the basal forebrain (BF) is known to modulate cortical activity and support attention, it remains unclear whether BF activity directly conveys an attention signal. Here, we show that selective attention to auditory and visual stimuli converges onto a shared population of noncholinergic BF neurons. Using a cross-modal task where rats rapidly switched attention between modalities, we found that these neurons responded strongly to attended targets but weakly to the same stimuli when ignored, regardless of modality. These effects closely tracked both task-driven and spontaneous attention shifts on a single-trial basis. Moreover, BF responses reflected the linear summation of attended and ignored inputs, suggesting that sensory streams are filtered in parallel before converging in the BF. These findings suggest that the BF may serve as a subcortical hub integrating attention signals across modalities to guide adaptive behavior.