Matthew Schmit

I have lived in Tucson my whole life, graduating from the UA as part of the second ever graduating class from the Neuroscience and Cognitive Science program here. As native Tucsonan, I spend a lot of my free time working with the community. I do this through science outreach, taking the neuroscience demonstration I helped build, called B the Brain, to the Tucson Festival of Books, as a guest in middle school classrooms, Flandreau Planetarium, the UA STEAM workshop, and many others to get the next generation of scientists excited and empowered. I also participate in the community through Polish folk dance as the artistic director of the Lajkonik Polish Folk Ensemble, adding to the rich cultural background of Tucson through festivals like the Tucson Meet Yourself, and by representing us Tucsonans at festivals out of state and internationally.

Research Summary

The Amygdala is a crossroads of information in the brain, integrating emotionally relevant information from all modalities and processing it in complex ways we do not understand, eventually directly influencing the entire brain, especially brain nuclei involved in basic survival functions like eating, threat responses, down to something as basic as thermoregulation. I want to understand how this information is integrated and processed from a neural circuits perspective. This means understanding what information different populations of neurons integrate and how that activity influences behavior. My work focuses on understanding the brain circuits involved in eating, or more specifically, not eating. Eating keeps us alive but choosing not to eat to avoid a predator or poisonous food, or to care for offspring can be just as important for survival. We understand very little about how this balance functions on a neurological level, what information goes into it, how motivational states play into this balance, but we know the amygdala is part of it. The central nuclei of the amygdala (CeA), specifically a subset of its neurons marked by the expression of protein kinase c-delta (PKCδ+), play a role in inhibiting feeding. When these neurons are silenced mice fail to reduce food intake in response to the satiety hormone cholecystokinin (CCK) or in response to visceral malaise. My main project involves studying these neurons in a normally behaving mouse using in-vivo calcium imaging. Before, we have manipulated the activity of these neurons in bulk, but how they naturally act during feeding is unknown. I am working to fill this gap. I also study how the projections from the insular cortex influence these neurons and feeding behaviors. Our data has shown that activating this pathway inhibits feeding. We employed computational modeling to explore the different circuit structures in the amygdala that could exits to produce feeding inhibition when this pathway is activated. This also lets us explore possible changes in brain state caused by activation in a more nuanced way.

Publications

Rodrigues Sanchez, M., Wang, Y., Cho, T.S., Schnapp, W.L., Schmit, M. B., Fang, C., Cai, H, Dissecting a disynaptic central amygdala parasubthalamic nucleus neural circuit that mediates cholecystokinin-induced eating suppression, (2022), Molecular Metabolism – Brief Communication doi: https://doi.org/10.1016/j.molmet.2022.101443

Zhang-Molina, C., Schmit, M. B., & Cai, H.  Neural circuit mechanism underlying the feeding controlled by insula-central amygdala pathway (2020) ISCIENCE, doi: https://doi.org/10.1016/j.isci.2020.101033

Burton, A., Obaid, S. N., Vázquez-Guardado, A., Schmit, M. B., Stuart, T., Cai, L., Chen, Z., Kandela, I., Haney, C. R., Waters, E. A., Cai, H., Rogers, J. A., Lu, L., & Gutruf, P. (2020). Wireless, battery-free subdermally implantable photometry systems for chronic recording of neural dynamics. Proceedings of the National Academy of Sciences, 10, 201920073.

Wang, Y., Kim, J., Schmit, M. B., Cho, T. S., Fang, C., & Cai, H. (2019). A bed nucleus of stria terminalis microcircuit regulating inflammation-associated modulation of feeding. Nature Communications, 10(1), 2769.

Ye, T., Bartlett, M. J., Schmit, M. B., Sherman, S. J., Falk, T., & Cowen, S. L. (2018). Ten-Hour Exposure to Low-Dose Ketamine Enhances Corticostriatal Cross-Frequency Coupling and Hippocampal Broad-Band Gamma Oscillations. Frontiers in Neural Circuits, 12.