Auditory Spatial Attention
Our research explores the omnidirectional mapping of auditory spatial attention when focusing directly in front, behind, to the left, and to the right. We examined the spatial profile of attention within each hemispace and across hemispaces with an auditory spatial target detection task where most stimuli originated from an attended (standard) location, honing in on sustained attention, with intermittent orienting to locations outside of focus. Attentional benefits accumulated at standards irrespective of hemispace. Auditory spatial attention gradients show a quadratic profile; however, the amplitude of the gradients depends on the locus of attention. The quadratic profile of spatial attention is more accentuated in the front vs. back hemispace and the same can be said about the right hemispace vs. left hemispace. We report right side of space advantage in the front hemispace irrespective of the locus of attention or spatial range of stimuli. The extension of spatial range of stimulus presentation from 180 to 360 resulted in a more homogenous distribution of spatial attention between nonstandard locations, except in the right side of space when endogenous attention was focused on midline standards. For spatial target detection accuracy, we found uniformly that as angular separation between standard and shift locations increase accuracy ratings progressively decrease. EEG results show monotonic increases in ERP amplitudes at N100 and P200 time-windows from attended to shift locations. In the P300 time-window, amplitudes increased at left and right parietal sites when orienting attention to shift locations in the opposite side of space.