Addiction Rehab: Extinction of Conditioned Opiate Withdrawal in Rats Is Blocked by Intracerebroventricular Infusion of an NMDA Receptor Antagonist.

Extinction of conditioned opiate withdrawal in rats is blocked by intracerebroventricular infusion of an NMDA receptor antagonist.

Filed under: Addiction Rehab

Neurosci Lett. 2013 Feb 12;
Coleman BR, Carlezon Jr WA, Myers KM

Maladaptive conditioned responses (CRs) contribute to psychiatric disorders including anxiety disorders and addiction. Methods of reducing these CRs have been considered as possible therapeutic approaches. One such method is extinction, which involves exposure to CR-eliciting cues in the absence of the event they once predicted. In animal models, extinction reduces both fear and addiction-related CRs, and in humans, extinction-based cue exposure therapy (CET) reduces fear CRs. However, CET is less effective in drug addicts, for reasons that are not clear. Increased understanding of the neurobiology of extinction of drug-related CRs as compared to fear CRs may help illuminate this issue. Here, we examine the N-methyl-D-aspartate (NMDA) receptor-dependence of extinction of conditioned opiate withdrawal in rats. Using a place conditioning paradigm, we trained morphine-dependent rats to associate an environment with naloxone-precipitated withdrawal. We then extinguished that association by returning the rats repeatedly to the environment in the absence of acute withdrawal. In some rats we administered the NMDA receptor antagonist D,L-2-amino-5-phosphovaleric acid (AP5) intracerebroventricularly immediately prior to extinction training. In a subsequent test session, these rats avoided the formerly naloxone-paired environment, similar to rats that had not undergone extinction training. By contrast, rats that received vehicle prior to extinction training did not avoid the formerly naloxone-paired environment. This finding indicates that extinction of a drug-related CR (conditioned opiate withdrawal) is dependent on NMDA receptors, similar to extinction of conditioned fear. The locus of the critical NMDA receptors is unclear but may include basolateral amygdala and/or medial prefrontal cortex.
HubMed – addiction


A novel in vivo atlas of human hippocampal subfields using high-resolution 3T magnetic resonance imaging.

Filed under: Addiction Rehab

Neuroimage. 2013 Feb 12;
Winterburn JL, Pruessner JC, Chavez S, Schira M, Lobaugh NJ, Voineskos AN, Chakravarty MM

The hippocampus is a neuroanatomical structure that has been widely studied in the context of learning, memory, stress, and neurodegeneration. Neuroanatomically, the hippocampus is subdivided into several subfields with intricate morphologies and complex three-dimensional relationships. Recent studies have demonstrated that the identification of different subfields is possible with high-resolution and -contrast image volumes acquired using ex vivo specimens in a small bore 9.4T scanner and, more recently, in vivo, at 7T. In these studies, the neuroanatomical definitions of boundaries between subfields are based upon salient differences in image contrast. Typically, the definition of subfields has not been possible using commonly available magnetic resonance (MR) scanners (ie: 1.5 or 3T) due to resolution and contrast limitations. To overcome the limited availability of post-mortem specimens and expertise in state-of-the-art high-field imaging, we propose a coupling of MR acquisition and detailed segmentation techniques that allow for the reliable identification of hippocampal anatomy (including subfields). High-resolution and -contrast T1- and T2-weighted image volumes were acquired from 5 volunteers (2 male; 3 female; age range: 29-57, avg. 37) using a clinical research-grade 3T scanner and have final super-sampled isotropic voxel dimensions of 0.3 mm. We demonstrate that by using these acquisition techniques, our data results in contrast-to-noise ratios that are compare well with high-resolution images acquired with long scan times using post-mortem data at higher field strengths. For the subfields, the cornus ammonis (CA) 1, CA2/CA3, CA4/dentate gyrus, stratum radiatum/stratum lacunosum/stratum moleculare, and subiculum were all labelled as separate structures. Hippocampal volumes are reported for each of the substructures and the hippocampus as a whole (range for hippocampus: 2456.72 – 3325.02 mm(3)). Intra-rater reliability of our manual segmentation protocol demonstrates high reliability for the whole hippocampus (mean Dice Kappa of 0.91; range 0.90-0.92) and for each of the subfields (range of Dice Kappas: 0.64-0.83). We demonstrate that our reliability is better than the Dice Kappas produced by simulating the following errors: a translation by a single voxel in all cardinal directions and 1% volumetric shrinkage and expansion. The completed hippocampal atlases are available freely online ( and can be coupled with novel computational neuroanatomy techniques that will allow for them to be customized to the unique neuroanatomy of different subjects, and ultimately be utilized in different analysis pipelines.
HubMed – addiction


Compulsive sexual behavior and psychopathology among treatment-seeking men in São Paulo, Brazil.

Filed under: Addiction Rehab

Psychiatry Res. 2013 Feb 14;
Scanavino MD, Ventuneac A, Abdo CH, Tavares H, Amaral ML, Messina B, Reis SC, Martins JP, Parsons JT

This study examined compulsive sexual behavior (CSB) and psychopathology in a treatment-seeking sample of men in São Paulo, Brazil. Eighty-six men (26% gay, 17% bisexual, 57% heterosexual) who met diagnostic criteria for excessive sexual drive and sexual addiction completed assessments consisting of the Mini International Neuropsychiatric Interview, a structured clinical interview for DSM-IV Axis I Disorders-Clinical Version (segment for Impulse Control Disorder), Sexual Compulsivity Scale (SCS), and questions about problematic CSB. The average SCS score for our sample was above the cut-off score reported in other studies, and 72% of the sample presented at least one Axis I psychiatric diagnosis. There were no differences among gay, bisexual, and heterosexual men on SCS scores and psychiatric conditions, but gay and bisexual men were more likely than heterosexual men to report casual sex and sex with multiple casual partners as problematic behaviors. SCS scores were associated with psychiatric co-morbidities, mood disorder, and suicide risk, but diagnosis of a mood disorder predicted higher SCS scores in a regression analysis. The study provides important data on the mental health needs of men with CSB in São Paulo, Brazil.
HubMed – addiction


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