Abstract
Attention to the left and right visual field is lateralized to right and left temporoparietal processing regions, respectively. Our stable visual percept suggests a complex relationship between these lateralized regions, yet this interaction is poorly understood. Here we test if lateralized attention regions interact via mutual inhibition. According to the mutual inhibition hypothesis, isolating attention to the right visual field (for example) should boost activity in the left attention regions, leading to the inhibition of the right attention regions, culminating in a decrease in attention in the left visual field. To investigate this hypothesis, we presented bilateral multiple object tracking (MOT) stimuli to our participants (n=42), but had them isolate attention to one visual field for 30 minutes. We tested bilateral MOT before and after attention isolation to determine impact to the unattended visual field. Our participants were split into three groups: 1) attention isolated to right visual field (eye-tracker to ensure central fixation), 2) attention isolated to the left visual field, and control group 3) attend bilaterally using bilateral MOT. Surprisingly, we found attention isolation increased attention to the unattended visual field (Left: t(13)2.98,p=0.01; Right: t(13)3.05,p=0.009). The difference between visual fields after isolation was significant when attention was isolated right (p=0.044), but not left (p=0.98). Furthermore, when attention was isolated right, there was a significantly difference between the unattended visual field and the control (p=0.032). These results suggest prolonged activation of attention regions in one hemisphere does not subsequently inhibit attention regions in the opposite hemisphere, suggested by the mutual inhibition hypotheses. Instead, prolonged activation results in a boost of attention to the unattended visual field. The different impact of attention isolation to the left visual field provides elegant evidence of distinctive roles between lateralized attention regions, supporting a bilateral orientation vector in right temporoparietal areas.