Biological psychiatry
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Biological psychiatry · Mar 2015
Multicenter Study Comparative StudyIn vivo hippocampal subfield volumes in schizophrenia and bipolar disorder.
Hippocampal dysfunction and volume reductions have been reported in patients with schizophrenia and bipolar disorder. The hippocampus consists of anatomically distinct subfields. We investigated to determine whether in vivo volumes of hippocampal subfields differ between clinical groups and healthy control subjects. ⋯ Hippocampal subfield volume reductions are found in patients with schizophrenia and bipolar disorder. The magnitude of reduction is greater in patients with schizophrenia, particularly in the hippocampal outflow regions presubiculum and subiculum.
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Biological psychiatry · Mar 2015
Chronic cannabinoid receptor 2 activation reverses paclitaxel neuropathy without tolerance or cannabinoid receptor 1-dependent withdrawal.
Mixed cannabinoid receptor 1 and 2 (CB1 and CB2) agonists such as Δ(9)-tetrahydrocannabinol (Δ(9)-THC) can produce tolerance, physical withdrawal, and unwanted CB1-mediated central nervous system side effects. Whether repeated systemic administration of a CB2-preferring agonist engages CB1 receptors or produces CB1-mediated side effects is unknown. ⋯ Our results highlight the potential of prolonged use of CB2 agonists for managing chemotherapy-induced allodynia with a favorable therapeutic ratio marked by sustained efficacy and absence of tolerance, physical withdrawal, or CB1-mediated side effects.
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Biological psychiatry · Mar 2015
ReviewAnticipatory reward processing in addicted populations: a focus on the monetary incentive delay task.
Advances in brain imaging techniques have allowed neurobiological research to temporally analyze signals coding for the anticipation of reward. In addicted populations, both hyporesponsiveness and hyperresponsiveness of brain regions (e.g., ventral striatum) implicated in drug effects and reward system processing have been reported during anticipation of generalized reward. We discuss the current state of knowledge of reward processing in addictive disorders from a widely used and validated task: the monetary incentive delay task. ⋯ Divergent results across abstinent, recreationally using, and addicted populations demonstrate complexities in interpreting findings. Future studies would benefit from focusing on characterizing how impulsivity and other addiction-related features relate to anticipatory striatal signaling over time. Additionally, identifying how anticipatory signals recover or adjust after protracted abstinence will be important in understanding recovery processes.