Abstract
A juvenile songbird learns to sing by imitating the song of an adult tutor, providing a spectacular example of spontaneous, intrinsically motivated motor learning. Despite decades of effort, the neural mechanisms that guide juvenile song learning remain poorly understood. Recent experiments from our group show that endogenous dopamine signalling in a song-specialized part of the basal ganglia acts like a compass to point the juvenile towards its song learning outcome. Furthermore, we find that dopamine release in the basal ganglia is regulated not only by midbrain neurons classically associated with reinforcement learning but also by local cholinergic signalling driven in a top-down manner by cortical song premotor inputs. Notably, while both dopamine and acetylcholine signalling in the basal ganglia are necessary to learning, only the dopamine signal conveys instructive information about song quality. Lastly, the highly convergent and multiplexed nature of corticostriatal input in the rodent basal ganglia has made it challenging to identify a synaptic locus of reinforcement learning. In contrast, the songbird basal ganglia receive just two cortical inputs, both of which are specialized for song. I will describe how we are combining optogenetic, chemogenetic, computational and behavioural methods to identify a synaptic locus for song learning.
Biography
Richard Mooney is the Geller Professor of Neurobiology in the Department of Neurobiology in the Duke University School of Medicine. Motivated by a longstanding interest in neuroscience and music, he and his colleagues study the brain mechanisms that enable birdsong learning and, more generally, vocal communication. He obtained his BS in Biology from Yale University, his Ph.D. in Neurobiology from Caltech, and pursued postdoctoral training at Stanford University before joining the Duke faculty as an assistant professor in 1994. Dr. Mooney has received the Moore Visiting Fellowship at Caltech, Dart Foundation Scholar’s Award, McKnight Investigator Award, Sloane Research Fellowship, Klingenstein Research Fellowship, and the Helen Hay Whitney Fellowship. He was also honoured to receive the Master Teaching Award, the Davison Teaching Award, and the Langford Prize from Duke University. He was elected to the American Academy of Arts and Sciences in 2020 and to the National Academy of Sciences in 2024.