Abstract:
The primary input area of the basal ganglia, the striatum, plays a role in integrating signals from the cortex, midbrain, and thalamus to make associations between stimuli, actions, and rewards. The canonical view has been that midbrain activity drives all dopamine signals in the striatum. However, recent findings have forced the field to reconsider this viewpoint: cortical and thalamic inputs to the striatum can also produce large, local dopamine signals indirectly through striatal cholinergic interneurons. Here, we aimed to determine how dopamine, specifically cholinergic-evoked dopamine, may be involved in visual learning. This would reveal a novel mechanism for learning specific associations that is not explicable with current models and would be consistent with recent evidence linking visual cortico-striatal circuits to visual learning. We trained mice on a unilateral orientation-change detection task while recording fluorescent dopamine signals bilaterally in the dorsomedial or dorsolateral striatum to explore how task-related dopamine signals evolved with experience and increased performance. We found both subregion-dependent and performance-dependent differences in dopamine signals across the course of training. We then used ex vivo fast-scan cyclic voltammetry and whole-cell electrophysiology to explore performance-dependent differences in electrically and optogenetically evoked dopamine as well as corticostriatal connectivity with cholinergic interneurons. Our findings provide surprising information regarding corticostriatal connectivity and the neural circuits involved in visual learning and sensory perception.
Location: Bethesda campus, Bldg. 35, room 640. Refreshments will be served!
Webex link: https://nih.webex.com/nih/j.php?MTID=m7d7a7bd3b9c55e1640bb57002af339d5
Password: NBIG