Biology subjects

Choi, D.-S.

Publications and source records attributed to Choi, D.-S..

3 recordsLinked to original sources

bioRxiv2025

Caspase-dependent ablation of indirect medium spiny neurons projecting to external globus pallidus promotes compulsive ethanol-seeking and drinking behaviors

The dorsomedial striatum (DMS) is primarily recognized for regulating goal-directed reward-seeking behaviors, while the dorsolateral striatum (DLS) is predominantly associated with movement and habitual behaviors. In this study, we sought to investigate two pathways, direct medium spiny neuron (dMSN) and indirect medium spiny neuron (iMSN) in the two dorsal striatal subregions (DMS and DLS) in ethanol-seeking and drinking behaviors. Here, we selectively ablated iMSNDMS[->]GPe and iMSNDLS[->]GPe and trained mice to exhibit goal-directed and habitual reward-seeking behaviors using random ratio (RR) and random interval (RI) operant conditioning, respectively. We found that partial ablation of iMSNDLS[->]GPe exhibited increased resilience to bitter-tasting ethanol solution when subjected to quinine adulterated reward in operant conditioning paradigms, suggesting compulsive-like seeking behavior. Consistently, in a separate cohort of mice, we found that the iMSNDLS[->]GPe ablated mice show higher preference and consumption of quinine adulterated ethanol solution than control mice in two-bottle choice continuous access drinking, with increasing quinine concentration and exhibit more compulsive-like behavior. On the other hand, ablation of iMSNDMS[->]GPe resulted in insensitivity to satiety-based reward devaluation in RR-trained mice, consistent with a shift toward habitual behavior but no change in compulsive ethanol-seeking and drinking behavior. Together, our findings demonstrate that DLS iMSN function is essential in inhibiting compulsive-like behavior.

neuroscience↗

bioRxiv2025

Pallidal prototypic neuron and astrocyte activities regulate flexible reward-seeking behaviors

Behavioral flexibility allows animals to adjust actions to changing environments. While the basal ganglia are critical for adaptation, the specific role of the external globus pallidus (GPe) is unclear. This study examined the contributions of two major GPe cell types--prototypic neurons projecting to the subthalamic nucleus (ProtoGPe[->]STN neurons) and astrocytes--to behavioral flexibility. Using longitudinal operant conditioning with context reversals, we found that ProtoGPe[->]STN neurons dynamically represent contextual information correlating with behavioral optimality. In contrast, GPe astrocytes exhibited gradual contextual encoding independent of performance. Deleting ProtoGPe[->]STN neurons impaired adaptive responses to changing action-outcome contingencies without altering initial reward-seeking acquisition, highlighting their specific role in enabling behavioral flexibility. Furthermore, we discovered that ProtoGPe[->]STN neurons integrate inhibitory striatal and excitatory subthalamic inputs, modulating downstream basal ganglia circuits to support flexible behavior. This research elucidates the complementary roles of ProtoGPe[->]STN neurons and astrocytes in cellular mechanisms of flexible reward-seeking behavior.

neuroscience↗

bioRxiv2023

From asexuality to sexual reproduction: cyclical switch of gametogenic pathways in hybrids depend on ploidy level

The cellular and molecular mechanisms governing sexual reproduction is highly conserved across eukaryotes. Nevertheless, hybridization can disrupt such machinery leading to asexual reproduction. To investigate how hybridization and polyploidization affect gametogenesis and reproductive outcomes of asexual hybrids, we conducted a comprehensive study on diploid and triploid hybrids along with their sexual parental species from the freshwater fish family Cobitidae. In diploid and triploid hybrids, most gonocytes maintain their original ploidy level. During meiosis, such gonocytes experience abnormal chromosome pairing preventing progression beyond pachytene. Diploid hybrid females regain fertility through premeiotic genome endoreplication, resulting in the rare emergence of tetraploid gonocytes. Tetraploid gonocytes bypass meiosis and lead to clonal diploid gametes. In contrast, triploid hybrids lack genome endoreplication but utilize premeiotic genome elimination of a single-copy parental genome forming diploid gonocytes that undergo meiosis and produce haploid gametes. Therefore, the interplay of parental genomes leads to diverse gametogenic outcomes in hybrids dependent on their ploidy and genome dosage. These alterations in gametogenic pathways can persist across generations, potentially enabling the cyclic maintenance of asexual/polyploid hybrids in natural populations.

evolutionary biology↗