View clinical trials related to Placebo.
Filter by:To provide an initial test of the hypothesis that dopamine mediates the motivational salience of stimuli beyond simple stimulus-reinforcement associations, the researchers propose to undertake a study of the modulation of a) levels of agreement or disagreement with; b) the perceived self- relevance; and c) the perceived interest of propositions expressing beliefs and values in healthy male volunteers using Ii) a dopamine antagonist (the D2-blocker haloperidol), and (ii) a dopamine precursor L-Dopa to increase CNS dopamine transmission. The researchers will also administer the Salience Attribution Task (SAT) which will allow researchers to assess reward-learning processing of simple stimuli using a reaction-time game. This task was utilised by Roiser et al in order to explore whether delusions in medicated patients with schizophrenia were related to impairments in associative learning. The authors hypothesised that associative learning was influenced by D2 receptor blockade. The researchers extend this approach to examine the effect of dopamine modulation on the SAT as a measure of associative learning, a basic neuropsychological process that may be involved in the attribution of salience to beliefs. Finally, the researchers will ask participants to perform a within-subjects dictator game to understand the influence of dopaminergic manipulation of the live attribution of harm intention to partners. The task has been previously validated online. Participants will play against 3 partners in a random order in each drug condition. Each partner will play the participant for 6 trials. One partner will always be fair, one will always be unfair, and one will be 50% unfair. We aim to understand whether potentiating dopamine has an additive effect on the harm intention attributions toward partners, regardless of the behaviour of the partner.
Background: - Stress can cause people to give in to temptations to eat less healthily. People who are on weight loss diets often have problems sticking to their diets when they are stressed. Some tests have shown that the drug pexacerfont can help reduce stress-related seeking of high-calorie foods. However, it has not been tested on reducing food craving. Researchers want to test pexacerfont on people who are on diets to see if it can reduce stress-related food cravings. Objectives: - To see if pexacerfont can help reduce stress-induced food cravings. Eligibility: - Individuals between 21 and 65 years of age who are on a diet to control their weight. Design: - Participants will be screened with a physical exam and medical history. This study requires seven visits over about 35 days. - Participants will take either pexacerfont or placebo pills during the study. They will have three pills every morning. They will record video of themselves taking the pills every day. - Every evening, participants will fill out a questionnaire. It will ask questions about feelings and behaviors related to eating and food craving. - Participants will have regular study visits while taking the pills. The visits will involve questions about stressful situations and food cravings. One visit will involve a mildly stressful math test, followed by tasting of different foods. This test will look at whether pexacerfont can affect food preferences. Participants will provide blood and saliva samples as directed at these study visits. - Participants will have follow-up phone calls 1, 3, and 6 months after the end of the study.
The goal of this study is to determine whether a study medication (d-cycloserine) improves the ability of older adults to perform on tests of neuropsychological functioning. Tests of neuropsychological functioning assess attention, memory, and executive functioning skills (for example, problem-solving, planning and organizing skills). It was hypothesized that participants who received study medication would perform better on neuropsychological tests than would participants who received the sugar pill.
The objective of this study is to verify if there is a neurophysiologic reserve when caffeine and placebo perceived as caffeine are manipulated in closed- and opened-loop exercises. Parameters of excitability level of skeletal muscle and Central Nervous System (CNS), and peripheral metabolism will be measured
Positive social relationships have consistently been associated with better health, although the neurobiological underpinnings of these observed effects remain largely unknown. The overall goal of the proposed work is to explore novel biological pathways that may explain how social relationships influence health. Recent theorizing suggests that the oxytocin system may underlie some of the observed beneficial effects. Four hypotheses will be examined: 1. Oxytocin ameliorates the deleterious neuroendocrine, cardiovascular, and subjective effects of stress. 2. Oxytocin and social support have similar and additive stress-buffering effects. 3. Effects of oxytocin are evident among younger and older adults. 4. Effects of oxytocin are stronger in women vs men.
The study is aimed to evaluate the efficacy of antiglutamate anticonvulsants (topiramate, lamotrigine, and memantine) in the treatment of alcohol withdrawal syndrome