A brain network called the default mode network (DMN), previously studied mainly in humans and primates, also exists in rats. The DMN in rats is broadly similar to that in nonhuman primates and humans, suggesting it is a fundamental feature of mammalian brains. The network appears to integrate sensory and emotional information to guide behavior in anticipation of changing environmental conditions, despite the distinct evolutionary paths of rodents and primates. The findings help clarify the DMN's core functions, which remain poorly understood in humans.
After a low oral dose of MDMA (1.0 mg/kg), average maximum plasma concentrations were 162.9 ng/mL for MDMA and 171.9 ng/mL for its metabolite HMMA. After a high dose (1.6 mg/kg), MDMA's average maximum concentration rose significantly to 291.8 ng/mL, while HMMA's remained unchanged at 173.5 ng/mL, indicating nonlinear pharmacokinetics. The half-lives of MDMA, MDA, and HMMA ranged from roughly 7 to 13.5 hours. This study provides the first MDMA plasma pharmacokinetic data from Black participants and female participants, with more frequent and extended sampling than prior work.