1.  To understand how feedback about performance is encoded in the brain, we combine chronic neural recordings from singing birds with manipulations of auditory feedback to characterize how signals in this circuit change in response to persistent vocal errors. While initial experiments focus on the contributions of the cortical output nucleus of this circuit, we will also investigate how auditory feedback-related signals are transformed at different stages in the circuit.

2.  To directly test how signals in this circuit drive adaptive changes in song, we use electrical, chemical, and optogenetic methods to alter neural activity during normal vocal behavior and in response to disruption of auditory feedback. Such experiments will help to elucidate which patterns of activity are necessary and/or sufficient to drive acute and/or long-lasting changes to song.

3. In many species of birds, sensory learning of song occurs during an early critical period, and the influence of auditory feedback on song production declines with age. To investigate whether the mechanisms that mediate feedback-driven changes in adult song are the same as those that enable juvenile motor learning, we record singing-related activity in the basal ganglia-thalamo-cortical circuit in juvenile birds engaged in sensorimotor learning. Comparison of neural activity patterns at different stages of learning will shed light on the neural processes that enable or limit auditory feedback-driven song plasticity. For example, does burst firing or variability in spike timing decrease as vocal output approaches the target? Just as in adult birds, we use electrical, pharmacological, and optogenetic techniques to directly alter patterns of neural activity in this circuit and assess their causal role in learning.

4.  Cholinergic modulation of basal ganglia activity and song performance  Dysregulation of neuromodulators is a prominent feature of basal ganglia movement disorders, but how cholinergic signaling modulates movement-related firing patterns remains unclear.  Using chronic extracellular recordings, we are characterizing the singing-related activity of striatal cholinergic interneurons.  We are also investigating how selective loss of cholinergic interneurons affects activity in the basal ganglia circuit and regulation of motor variability.

5.  Developing an animal model of rhythm perception (currently hiring)                             In collaboration with Dr. Annirudh Patel in the Psychology Department, we are investigating the role of auditory-motor interactions in flexible rhythmic pattern perception.  We have shown that zebra finches can recognize beat-based rhythms in a flexible manner, and are now testing the hypothesis that a vocal premotor brain region is necessary for rhythm perception. This project is part of the SoundHealthNetwork:  https://soundhealth.ucsf.edu/projects-view