The Role of the Pulvinar in Selective Visual Attention

Abstract

Our visual system has a limited capacity to process the complex, cluttered environment around us. Information relevant to guiding our current behavior needs to be selectively enhanced. This process is known as selective visual attention. Lesion studies and electrophysiological recordings reveal a network of brain areas, including the pulvinar nucleus of the thalamus, that is important for visual attention. However, the role of the pulvinar in visual attention and how it interacts with other areas is poorly understood. To approach this problem, we first developed novel methods to to record neuronal activity from multiple subdivisions of the pulvinar in macaque monkeys using multi-electrode arrays while they performed a spatial attention task. During the period of the task when attention was maintained, spiking activity of putative inhibitory neurons in the pulvinar was suppressed, suggesting that attention operates through selective disinhibition of pulvinar relay cells. In addition, spikes from dorsal pulvinar neurons synchronized with the local field potential in the ventral pulvinar during attention, which suggests that the dorsal pulvinar and connected attentional control areas may bias early visual areas by modulating ventral pulvinar activity. Secondly, we identified low-dimensional structure in pulvinar population spiking activity that suggests oscillatory-like dynamics in spiking during sustained attention. Finally, we recorded neuronal activity simultaneously from the lateral pulvinar and two interconnected cortical areas and examined network interactions during attention. We found evidence suggesting that the pulvinar synchronizes oscillatory activity between cortical areas during attention and may also support sustained, elevated spiking activity in these areas. Together, these results provide a more comprehensive understanding of the thalamic and thalamo-cortical networks underlying selective visual attention.