PROJECT SUMMARY
Acetylcholine (ACh) release in the dorsomedial striatum (DMS) is important for reversal learning, a form of
cognitive flexibility impaired in schizophrenia and other psychiatric and neurologic disorders. Thalamic activity is
necessary for DMS ACh release, and functional connectivity between the thalamus and the dorsal striatum is
impaired in schizophrenia and other disorders, suggesting thalamostriatal regulation of ACh release may be a
potential target for treatment of impaired cognition. However, it is unknown when and how thalamostriatal
projections regulate striatal ACh release to update behavior and facilitate neuronal value encoding during
reversal learning. To address this gap in knowledge, I will use a combination of fiber photometry, computational
modeling, optogenetics, and high-density in vivo electrophysiology. To test the hypothesis that DMS ACh release
accelerates learning rate, I will optogenetically inhibit DMS cholinergic interneurons during reward consumption
in a reversal learning task and I will use an advanced reinforcement learning model to determine how this affects
the rate at which the learning rate changes. To test the hypothesis that thalamostriatal projections are necessary
for DMS acetylcholine release and reversal learning, I will use a retrograde viral strategy to determine whether
projection-specific inhibition of thalamic inputs to the DMS during reward consumption decreases ACh release
and impairs reversal learning. Finally, to test the hypothesis that DMS ACh release expedites value updating in
medium spiny neurons I will simultaneously measure DMS ACh release with fiber photometry and striatal neuron
activity with electrophysiology to determine whether DMS ACh release correlates with the rate at which striatal
neurons update spike encoding of action value. This work will be performed at the New York State Psychiatric
Institute and the Columbia University Irving Medical Center Department of Psychiatry. Together these institutions
form a leading academic medical center and teaching hospital that has attracted a distinguished group of
research scientists who provide leadership in modern psychiatry. My long-term career goal is to become an
independent investigator studying the contribution of neuromodulation to behaviors and neural activity relevant
to mental disorders. I have a strong background in optogenetics, behavioral neuroscience, and fiber photometry,
which I will utilize in the proposed research. However, I still need additional training in advanced computational
modeling of behavior and in vivo electrophysiology with high-density silicon probes. I will receive this technical
training during the K01 award period, as well as professional development training to improve my grant-writing,
leadership, and science communication skills. The conducted research and training during this career
development award will increase my likelihood of success in becoming a leading neuroscientist and independent
investigator.