Hemispheric asymmetry of globus pallidus relates to alpha modulation in reward-related attentional tasks

Recent evidence suggests that the functional mechanisms of subcortical structures, such as the basal ganglia (BG),extend to the domain of attentional control. We here investigated the subcortical involvement in reward related top-down control of visual alpha-band oscillations (8 – 13 Hz), which has been consistently linked to the mechanisms supporting the allocation of visual spatial attention. Since items associated with contextual saliency (e.g. monetary reward or loss) draw attention, it is not surprising that alpha oscillations are further modulated by the acquired saliency properties of the visual items. The executive network controlling such reward-dependent modulations of oscillatory brain activity has yet to be fully elucidated, and likely relies on the contribution of subcortical regions. We hence investigated the predictive value of subcortical structural asymmetries on interhemispheric modulation of alpha power during a spatial attention task. We show that volumetric lateralization of globus pallidus (GP) and thalamus (Th) predicts individual hemispheric biases in the ability to modulate posterior alpha power. Our findings suggest that the Th and GP are differently implicated in a subcortical executive control network involved in modulating posterior alpha activity.