My research goal is to understand how cortico-striatal circuits, a neuronal circuit that is recognized to mediate goal-directed behaviors, play a role in reward valuation and reward prediction in rodents. 

Striatum has been related to motor planning and choices based on updated values from previous reward history. It integrates information from cortical circuits and sends downstream targets for action execution. Orbitofrontal cortex is known to be related to working memory and may involve top-down biasing on the response selection process in the basal ganglia and dopamine system. However how these two brain areas interact in trial by trial and make a choice is not clear. Using large scale electrophysiology in different brain areas simultaneously, I would like to investigate functional specialization not only in different brain areas but also within the striatum along the dorsal/ventral axes. With decoding analysis and neural network modeling, I would like to address the hierarchical structure in the brain circuits to lead goal-directed decisions. Furthermore, by optogenetically manipulating, I would like to investigate causal effects of specific brain circuits in the decision process.

Jung, D., Kim, S., Sariev, A., Sharif, F., Royer, S. (2019) Dentate granule and mossy cells exhibit distinct spatiotemporal responses to local change in a one-dimensional landscape of visual-tactile cues. Scientific Reports 9, 9545.

Chung, J., Sharif, F., Jung, D., Kim, S., Royer, S. (2017) Micro-drive and headgear for chronic implant and recovery of optoelectronic probes. Scientific Reports 7(1) 2773

Kim, S., Cai, X., Hwang, J., Lee, D (2012). Prefrontal and striatal activity related to values of objects and locations. Front. Neurosci. 6 108

Kim, S., Bobeica, I., Gamo, N.J., Arnsten, A.F., and Lee, D. (2012) Effects of α-2A adrenergic receptor agonist on time and risk preference in primates. Psychopharmacology. 219:363-375.

Cai, X.†, Kim, S.† and Lee, D. (2011) Heterogeneous coding of temporally discounted values in the dorsal and ventral striatum during intertemporal choice. Neuron 69: 170-182.

Kim, S. and Lee, D. (2011) Prefrontal cortex and impulsive decision making. Biological Psychiatry 69: 1140-1146. 

Hwang, J. †, Kim, S. †, and Lee, D. (2009) Temporal discounting and inter-temporal choice in rhesus monkeys. Front. Behav. Neurosci. 3:9.

Kim, S., Hwang, J., Seo, H., and Lee, D. (2009) Valuation of uncertain and delayed rewards in primate prefrontal cortex. Neural Networks 22: 294-304.

Kim, S., Hwang, J., and Lee, D. (2008) Prefrontal coding of temporally discounted values during inter-temporal choice. Neuron 59: 161-172.