Behavioural brain research
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Randomized Controlled Trial
Motor and cognitive placebo-/nocebo-responses in Parkinson's disease patients with deep brain stimulation.
Expectation contributes to placebo and nocebo responses in Parkinson's disease (PD). Subthalamic nucleus (STN) deep brain stimulation (DBS) improves proximal more than distal movements whereas it impairs executive cognitive function such as verbal fluency (VF). We investigated how expectation modulates the pattern of motor improvement in STN-DBS and its interaction with VF. ⋯ These results indicate that positive motor expectations exert both motor placebo and cognitive nocebo responses by further enhancing the STN-DBS-effect on proximal movements and by impairing VF. The placebo response on motor performance resembles the clinically known STN-DBS-effect with stronger improvement in proximal than distal movements. The nocebo response on VF is likely due to implicit learning mechanisms associated with an expectation-induced placebo response on motor performance.
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Randomized Controlled Trial
Relationship between sexual satiety and motivation, brain androgen receptors and testosterone in male mandarin voles.
Androgen receptors participate in the neuroendocrine regulation of male sexual behavior, primarily in brain areas located in the limbic system. Males of many species present a long-term inhibition of sexual behavior after several ejaculations, known as sexual satiety. It has been shown in rats that androgen receptor expression is reduced 24h after a single ejaculation, or mating to satiety, in the medial preoptic area, nucleus accumbens and ventromedial hypothalamus. ⋯ Males exposed to receptive females showed an increase in AR and T expression in the bed nucleus of the stria terminalis (BNST), LS, MeA and VMH. Serum testosterone levels remained unchanged after 24h in males exposed to receptive females or males mated to satiety. These data suggest a relationship between sexual activity and a decrease in AR and T expression in specific brain areas, and a relationship between sexual motivation and increased AR and T expression in other brain areas, independently of testosterone levels.