Abstract
Environmental factors play a role in the development and severity of neuropsychiatric disorders. Externalizing disorders are characterized by disruptive, impulsive, and often aggressive behaviors, including difficulties with self-control, rule-breaking, and a tendency to act out in ways that may harm oneself or others. Externalizing disorders frequently co-occur with internalizing disorders, such as anxiety. Individuals experiencing both externalizing/internalizing disorders are often among the most likely to seek healthcare services, as this co-occurrence is associated with more severe symptomatology and greater functional impairment. Here, we investigated the impact of environmental enrichment (EE) on adgrl3.1, a gene associated with impulsivity and attention deficits in zebrafish (Danio rerio). This gene encodes a receptor involved in cell adhesion and signaling and has been linked to susceptibility to externalizing disorders. Zebrafish were reared in either standard or enriched environments (from 15 days-post fertilization), and attention, impulsivity, and anxiety-related phenotypes were assessed at adult stages (4 months-post fertilization) using the open field test and a 5-choice serial reaction time task. EE mitigated anxiety-related behaviors in adgrl3.1 knockouts, normalizing locomotor patterns and decreasing thigmotaxis. Although attention deficits were reduced in adgrl3.1-/- fish reared in EE, impulsive behaviors were not. Together, these findings suggest that while environmental enrichment (EE) mitigates externalizing and internalizing symptoms in adgrl3.1 mutants, impulsivity remains less responsive to EE used in this study, indicating its distinct resistance to modulation.