The parafascicular thalamus steers attention to facilitate learning

Cues that predict reward can acquire strong power to bias orientation and approach, directing seeking behaviors into close proximity with reward. The parafascicular thalamus (PF), part of the intralaminar complex, is well-placed as a neural hub for integrating subcortical sensory and attentional signals to generate actions that support cue-guided behavior. Neurons in the PF respond to sensory cues and encode features of head position, but little is known about how the PF is engaged in vivo during learning. Here, we recorded calcium activity in PF neurons using fiber photometry throughout a pavlovian conditioning task. We found that PF neurons developed sustained cue-evoked responses that scaled with associative learning and diminished with extinction. PF neurons preferentially signaled cue-directed orientations and body movements made during the cue, and their activity paused during reward consumption. Using optogenetics, we found that stimulation of PF neurons disrupted normal cue-directed orientation and impaired associative learning by promoting exaggerated ipsilateral turning behavior. Broadly, these results suggest an encoding profile by which the PF can support cue and reward approach behavior via dynamic regulation of head and body position. Together, our data demonstrate a thalamic region that is important for steering attention to facilitate cue-reward learning.