Biology subjects

Won, M.

Publications and source records attributed to Won, M..

5 recordsLinked to original sources

bioRxiv2026

Impaired Reinforcement Learning Underlying Explore-Exploit Decision Making in Theft Recidivists

Larceny imposes profound societal and economic burdens; however, punitive judicial measures frequently fail to deter recidivism. The neurobehavioral mechanisms driving habitual offending, whether instrumental or kleptomanic, in theft recidivists remain poorly understood. In this study, we investigated explore-exploit decision-making and underlying reinforcement learning architectures in theft recidivists with a 4-arm bandit task while prefrontal cortex (PFC) hemodynamics were continuously monitored using functional near-infrared spectroscopy (fNIRS). Model-free behavioral analyses revealed that non-kleptomanic (TR-K) but not kleptomanic (TR+K) theft recidivists accumulated significantly higher cumulative regret and made fewer optimal choices compared to control individuals without criminal records (CT). Model-based analyses through Variational Bayesian Analysis identified Q-learning with decay model as the optimal computational fit. Parameter extraction using the model demonstrated that the TR-K group exhibited a lower learning rate than CT and TR+K groups, indicating a learning deficit in updating action values following environmental feedback. fNIRS tracking of trial-by-trial latent reinforcement variables revealed that while PFC activity was modulated by these variables, group differences were characterized by static baseline hemodynamic shifts rather than rewirings of value-tracking neural circuits. These findings suggest that non-kleptomanic recurrent thefts may be associated with impaired reinforcement learning mechanisms, challenging current punitive deterrence models.

neuroscience↗

bioRxiv2026

Altered Social Cognition Associated with Kleptomanic and Instrumental Thefts

Theft, including shoplifting, extorts a pervasive societal and economic burden. However, the neurobehavioral mechanisms underlying recurrent theft remain sparsely understood. In this study, we investigated social cognition deficits in theft recidivists with kleptomania (TR+K) and instrumental theft recidivists without kleptomania (TR-K) compared to control subjects without criminal records (CT), for which the Social Norms Questionnaire (SNQ-22) to assess explicit moral knowledge, alongside the Dictator Game (DG) and Hawk-Dove Game (HDG) to evaluate discretionary and competitive resource allocation with others, respectively, were administered. Bayesian statistical analyses revealed that all groups demonstrated comparable social norm recognition in SNQ-22 and prosociality in the DG. However, distinct behavioral profiles emerged in specific contexts, such that TR+K exhibited more unfairness than CT and TR-K at discretionary resource allocations in the DG, whereas in the HDG, TR-K demonstrated more aggressive, resource-monopolizing responses, particularly when against an aggressive opponent, than CT and TR+K. These results suggest that theft recidivism may stem from contextual failures rather than general deficits in moral knowledge, which are distinct between TR+K rooted in the internal factor, such as heightened loss aversion, and TR-K characterized by impulsivity over the external factor, such as social conflicts with others.

neuroscience↗

bioRxiv2026

Higher Impulsivity in the Heterogeneous Structure of Theft Recidivists with and without Kleptomania

Impulsivity is associated with various maladaptive behaviors, although its specific role in criminology has remained largely unexplored. We investigated impulsivity in theft recidivists (TR) with and without a diagnosis of kleptomania (KA) compared to control (CT) subjects with no criminal record in this study. Impulsivity was measured using a 5-trial adjusting delay discounting task, and prefrontal cortical (PFC) hemodynamics were assessed using functional near-infrared spectroscopy. Self-report questionnaires were also administered to further evaluate the relationships between impulsivity, negative affect, and reward and punishment sensitivity. TR demonstrated significantly higher impulsivity than CT, along with altered dorsomedial PFC hemodynamic responses. In addition, negative affect was significantly higher in the TR than in the CT participants. Path analysis revealed that the moderation of negative affect on reward, but not punishment, sensitivity, mediated impulsivity in TR. Notably, heightened impulsivity was observed across the TR participants regardless of KA diagnosis, whereas severe depression specifically distinguished KA from TR without it. These findings suggest that while trait impulsivity associated with PFC alterations may be a universal feature of TR, recurrent theft may be a heterogeneous condition, with specific affective dysregulations contributing differently to TR. SIGNIFICANCE STATEMENTRecurrent thefts, such as shoplifting, are a devastating social problem, posing massive financial losses. Nonetheless, surprisingly nothing is known about the neurobehavioral mechanisms that drive people stealing. In fact, kleptomania is a psychiatric disorder that had been identified over 200 years ago, yet exceptionally few studies have investigated this psychiatric condition, and its mechanism remains essentially unknown to date. This study demonstrates that impulsivity is elevated among incarcerated individuals with recurrent thefts with and without a diagnosis of kleptomania, which is associated with the activity of the left dorsomedial prefrontal cortex. Conversely, heightened depression among negative affect is a unique characteristic to kleptomania, providing evidence of heterogeneity among theft recidivists.

neuroscience↗

bioRxiv2026

Behavioral Economic Profiles in Theft Recidivists with and without Kleptomania

Recurrent theft, such as shoplifting, is a devastating social problem that poses a significant economic burden on society. However, the neurobehavioral mechanisms underlying such criminal offenses remain barely understood. Here we investigated the behavioral economic profiles of theft recidivists (TR) with and without kleptomania. To identify the decision-making processes underlying stealing behaviors, the hypothetical purchase task and the balloon analogue risk task (BART) structured with gain and loss frames were administered, along with concurrent measurement of prefrontal cortex (PFC) activity during the BART using functional near-infrared spectroscopy. TR with kleptomania demonstrated heightened loss aversion and price sensitivity (elasticity) compared to TR without kleptomania and control subjects with no criminal records, with a significant correlation between these factors, suggesting that heightened loss aversion may contribute to higher elasticity. Moreover, the relative loss-to-risk aversion ratio was found to be positively and negatively associated with the right and left PFC, respectively, suggesting that an imbalance between left and right PFC activity may be involved in the altered behavioral economic profiles. These findings challenge the conventional view of theft as a reward-seeking behavior, revealing that an abnormally inflated fear of monetary loss may play a role in recurrent stealing in kleptomania.

neuroscience↗

bioRxiv2022

Endogenous sterol synthesis is dispensable for Trypanosoma cruzi epimastigote growth but not stress tolerance

In addition to scavenging exogenous cholesterol, the parasitic kinetoplastid Trypanosoma cruzi can endogenously synthesize sterols. Similar to fungal species, T. cruzi synthesizes ergostane type sterols and is sensitive to a class of azole inhibitors of ergosterol biosynthesis that target the enzyme lanosterol 14-demethylase (CYP51). In the related kinetoplastid parasite Leishmania donovani, CYP51 is essential, yet in Leishmania major, the cognate enzyme is dispensable for growth; but not heat resistance. The essentiality of CYP51 and the specific role of ergostane-type sterol products in T. cruzi has not been established. To better understand the importance of this pathway, we have disrupted the CYP51 gene in T. cruzi epimastigotes ({Delta}CYP51). Disruption of CYP51 leads to accumulation of 14-methylated sterols and a concurrent absence of the final sterol product ergosterol. While{Delta} CYP51 epimastigotes have slowed proliferation compared to wild type parasites, the enzyme is not required for growth; however,{Delta} CYP51 epimastigotes exhibit sensitivity to elevated temperature, an elevated mitochondrial membrane potential and fail to establish growth as intracellular amastigotes in vitro. Further genetic disruption of squalene epoxidase ({Delta}SQLE) results in the absence of all endogenous sterols and sterol auxotrophy, yet failed to rescue tolerance to stress in{Delta} CYP51 parasites, suggesting the loss of ergosterol and not accumulation of 14-methylated sterols modulates stress tolerance.

microbiology↗