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Pregnancy is a unique neuroplastic period in adult life. This longitudinal study tracked brain cortical changes during the peripartum period and explored how the type of childbirth affects these changes. We collected neuroanatomic, obstetric and neuropsychological data from 110 first-time mothers during late pregnancy and early postpartum, as well as from 34 nulliparous women evaluated at similar time points. During late pregnancy, mothers showed lower cortical volume than controls across all functional networks. These cortical differences attenuated in the early postpartum session. Default mode and frontoparietal networks showed below-expected volume increases during peripartum, suggesting that their reductions may persist longer. Results also pointed to different cortical trajectories in mothers who delivered by scheduled C-section. The main findings were replicated in an independent sample of 29 mothers and 24 nulliparous women. These data suggest a dynamic trajectory of cortical decreases during pregnancy that attenuates in the postpartum period, at a different rate depending on the brain network and childbirth type., (© 2024. The Author(s).)

Background: Use of illegal stimulants is associated with an increased risk of psychotic disorder. However, the impact of stimulant use on odds of first-episode psychosis (FEP) remains unclear. Here, we aimed to describe the patterns of stimulant use and examine their impact on odds of FEP., Methods: We included patients with FEP aged 18-64 years who attended psychiatric services at 17 sites across 5 European countries and Brazil, and recruited controls representative of each local population (FEP = 1130; controls = 1497). Patterns of stimulant use were described. We computed fully adjusted logistic regression models (controlling for age, sex, ethnicity, cannabis use, and education level) to estimate their association with odds of FEP. Assuming causality, we calculated the population-attributable fractions for stimulant use associated with the odds for FEP., Findings: Prevalence of lifetime and recent stimulant use in the FEP sample were 14.50% and 7.88% and in controls 10.80% and 3.8%, respectively. Recent and lifetime stimulant use was associated with increased odds of FEP compared with abstainers [fully adjusted odds ratio 1.74,95% confidence interval (CI) 1.20-2.54, P = .004 and 1.62, 95% CI 1.25-2.09, P < .001, respectively]. According to PAFs, a substantial number of FEP cases (3.35% [95% CI 1.31-4.78] for recent use and 7.61% [95% CI 3.68-10.54] for lifetime use) could have been prevented if stimulants were no longer available and the odds of FEP and PAFs for lifetime and recent stimulant use varied across countries., Interpretation: Illegal stimulant use has a significant and clinically relevant influence on FEP incidence, with varying impacts across countries., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Vulnerability to addiction may be given by the individual's risk of developing an addiction during their lifetime. A challenge in the neurobiology of drug addiction is understanding why some people become addicted to drugs. Here, we used positron emission tomography (PET) and statistical parametric mapping (SPM) to evaluate changes in brain glucose metabolism in response to chronic morphine self-administration (MSA) in two rat strains with different vulnerability to drug abuse, Lewis (LEW) and Fischer 344 (F344). Four groups of animals were trained to self-administer morphine or saline for 15 days. 2-deoxy-2-[ 18 F]-fluoro-D-glucose (FDG)-PET studies were performed on the last day of MSA (acquisition phase) and after 15 days of withdrawal. PET data were analyzed using SPM12. LEW-animals self-administered more morphine injections per session than F344-animals. We found significant brain metabolic differences between LEW and F344 strains in the cortex, hypothalamus, brainstem, and cerebellum. In addition, the different brain metabolic patterns observed after the MSA study between these rat strains indicate differences in the efficiency of neural substrates to translate the drug effects, which could explain the differences in predisposition to morphine abuse between one individual and another. These findings have important implications for the use of these rat strains in translational morphine and opiate research., (© 2022. The Author(s).)

Endomorphin-1 (EM-1) and endomorphin-2 (EM-2) are two endogenous tetrapeptides with very high affinities for the μ-opioid receptor. Until recently, the precise neuroanatomical localization of the binding sites for these peptides was unknown. However, the recent synthesis of tritiated forms of these molecules has permitted these binding sites to be analysed with a very high degree of neuroanatomical specificity. Preliminary studies demonstrated a superior binding profile for EM-2, with less non-specific binding than EM-1. As the endogenous cannabinoid and opioid systems interact at several levels, we investigated how deletion of the CNR1 gene, which encodes the cannabinoid receptor 1 (CB(1)R) protein, affects the brain distribution of EM-2 binding sites. Our results revealed no differences in the average density of EM-2 binding sites in CB(1) receptor knockout (CB(1)R KO) and WT mice. However, when both hemispheres were analysed separately, we detected specific alterations in the distribution of EM-2 binding sites in the right hemisphere of CB(1)R KO mice. While, the density of EM-2 binding sites in CB(1)R KO mice was higher in the CA3 hippocampal field and in the pontine tegmental nuclei, it was lower in the superior colliculus and ventral tegmental area than in WT controls. No differences were observed in the left hemisphere for any of the regions analysed. For the first time these findings demonstrate a lateralization effect on cerebral opioid binding sites that may be mediated by the central cannabinoid system., (Copyright © 2012 Elsevier B.V. All rights reserved.)