Behavioural brain research
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Evidence from previous voxel-based morphometry (VBM) studies revealed that widespread brain regions are involved in chronic smoking. However, the spatial localization reported for gray matter (GM) abnormalities is heterogeneous. The aim of the present study was quantitatively to integrate studies on GM abnormalities observed in chronic smokers. ⋯ The convergent findings of this quantitative meta-analysis reveal a characteristic neuroanatomical pattern in chronic smokers. Future longitudinal studies should investigate whether this brain morphometric pattern can serve as a useful target and a prognostic marker for smoking intervention.
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The beneficial effects of physical exercise to reduce anxiety and depression and to alleviate stress are increasingly supported in research studies. The role of ovarian hormones in interactions between exercise and anxiety/stress has important implications for women's health, given that women are at increased risk of developing anxiety-related disorders, particularly during and after the menopausal transition. In these experiments, we tested the hypothesis that estrogen enhances the positive impact of exercise on stress responses by investigating the combined effects of exercise and estrogen on anxiety-like behaviors and stress hormone levels in female rats after an acute stressor. ⋯ In contrast, stress-induced elevations of stress hormone levels were attenuated by exercise experience in estrogen-treated rats, but were increased in rats without estrogen. These results suggest that voluntary exercise may be more effective at reducing stress hormone levels if estrogen is present. Additionally, exercise experience, or the distance run, may be important in reducing stress.
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Physical exercise can improve cognition but whether this is related to motivation levels is unknown. Voluntary wheel running is a rewarding activity proposed as a model of motivation to exercise. To question the potential effects of exercise motivation on subsequent behaviour, we used a pharmacological approach targeting some reward mechanisms. ⋯ Intermittent exercise was not associated with changes in behavioural or cognitive performance. The persistent reduction in exercise levels triggered by sulpiride also had limited impact on behavioural performance, although the level of performance for some behaviours was related to the level of exercise. Altogether, these findings indicate that corticosterone and dopamine D2/D3 receptor activation contribute to the motivation for wheel running, but suggest that motivation for exercise is not a sufficient factor to alter behaviour in healthy mice.
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The current study was designed to examine the involvement of cannabinoid CB1 receptors in the basolateral amygdala (BLA) in scopolamine-induced memory impairment in adult male Wistar rats. The animals were bilaterally implanted with the cannulas in the BLA and submitted to a step-through type passive avoidance task to measure the memory formation. The results showed that intraperitoneal (i.p.) administration of different doses of scopolamine (0.5-1.5mg/kg) immediately after the training phase (post-training) impaired memory consolidation. ⋯ Moreover, the blockade of the BLA CB1 receptors by 0.3ng/rat of AM251 prevented ACPA-induced improvement of the scopolamine response. In view of the known actions of the drugs used, the present data pointed to the involvement of the BLA CB1 receptors in scopolamine-induced memory consolidation impairment. Furthermore, it seems that a functional interaction between the BLA endocannabinoid and cholinergic muscarinic systems may be critical for memory formation.
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Cocaine has long been known to produce an initial "high" followed by an aversive/anxiogenic "crash". While much is known about the neurobiology of cocaine's positive/rewarding effects, the mechanisms that give rise to the drug's negative/anxiogenic actions remain unclear. Recent research has implicated the lateral habenula (LHb) in the encoding of aversive events including the anxiogenic response to cocaine. ⋯ Vehicle-pretreated controls developed approach-avoidance conflict behaviors about goal-box entry reflective of the dual positive and negative effects of cocaine. These behaviors were significantly diminished during LHb-D2 receptor antagonism and increased by the LHb D2 receptor agonist. These results demonstrate that activity at the D2 receptor in the lateral habenula serves to modulate the anxiogenic response to cocaine.