Determining the role of the pulvinar in visual attentional control

Abstract

Visual attentional control is a behavior that is critical for survival; despite its importance, the specific neural mechanisms underlying the process remain unclear. Upon perception, visual information is routed from the retina through the thalamus, which relays signals to the cortex for further processing. The pulvinar, a nucleus of the thalamus, has strong connections to both visual cortex (V1) and areas involved with attentional control, such as the superior colliculus and prefrontal cortex. The pulvinar has been implicated in attentional control from studies of human patients, as pulvinar lesions are correlated with an inability to ignore distracting visual information during performance of a behavioral task. Studies have also shown that mice are capable of learning similar tasks; given that their visual system is highly analogous to that of humans, mice serve as an optimal model for important behaviors such as visual attentional control. We targeted mouse pulvinar neurons with a GCaMP-expressing virus to allow measurement of brain activity through a cranial window. Utilizing both widefield and two-photon microscopic imaging, we found that axons projecting from the pulvinar to V1 are visually responsive and appear to be organized in a retinotopic manner. Future work on this project will include introduction of a visually guided behavioral task alongside silencing of pulvinar neurons using a DREADDs-expressing virus. We expect to find that, when mouse pulvinar neurons are silenced, important signals for visual attention sent from the thalamus to V1 will be interrupted, resulting in poor performance of a task requiring visual attentional control.