Recording and Modulation of Neuronal Mechanisms During Operant Conditioning: a MEG Study
- Most of the time, humans make decisions according to their consequences, especially if they will be beneficial, and will avoid or try to avoid doing an action if it has a bad outcome. The way that the brain prepares a movement has been studied in detail, but the way the brain makes decisions before carrying out an action is still poorly understood. Researchers are interested in learning more about the decision-making process and how it affects the brain.
- To record the activity of the brain during decision-making processes.
- Healthy, right-handed volunteers between 18 and 40 years of age.
- Potential participants will have a screening visit with a medical history and neurological examination to determine eligibility.
- This study requires seven visits: one magnetic resonance imaging (MRI) visit and 6 magnetoencephalography (MEG) recording visits. The MEG recording visits will include transcranial magnetic stimulation (TMS). All visits will be spaced at least 1 week apart. Total participation will last about 6 weeks.
- Participants will have an MRI scan at the first study visit.
- The MEG procedures will record brain activity during a series of computer tests involving winning or losing money. TMS will be performed during these visits, separate from the test.
Central Nervous System
|Study Design:||Time Perspective: Cross-Sectional|
|Official Title:||Recording and Modulation of Neuronal Mechanisms During Operant Conditioning: A MEG Study|
- Performance of each subject, before and after each cTBS session. We will measure their reaction time and the number of errors which corresponds to the number of times the subject did not choose the target which could have made him/her win money... [ Time Frame: During the MEG recording ]
- MEG signal: latency and amplitude of evoked and induced activity related to decision-making, without and after cTBS. The cerebral sources of these activities will also be computed and their interaction will be studied using source coherence ana... [ Time Frame: During the MEG recording ]
|Study Start Date:||October 2009|
The objective is to study cerebral activity associated with reward-related decision making. We plan to analyze and localize electrical activity of the brain related to such processes with magnetoencephalography (MEG). We also want to modulate the activity of these areas using repetitive transcranial magnetic stimulation (rTMS). We would like to analyze the consequences of these procedures on both brain activity and behavioral performance. This protocol will provide new information on cortical regions involved in decision-making and how these areas communicate with one another.
50 right-handed adult healthy volunteers.
A probabilistic reversal task will be performed: subjects will have to choose between pairs of stimuli associated with changing probabilities of rewards and losses. Using MEG, their cerebral activity will be recorded during task performance.
Since we want to modulate the cortical activity of cerebral areas involved in reward-related decision making, the study will be carried out in 8 different visits (screening visit, structural MRI acquisition and 6 recordings visits). In one visit, decision-making will be studied with no previous cortical stimulation. In 3 visits, decision-making will be studied after stimulation of one of 3 regions of interest. In one visit, decision-making will be studied after stimulation of a cortical area that is not thought to be involved in the process. Lastly, decision-making will be analyzed following a sham stimulation to test a possible placebo effect of rTMS.
Outcome measures are as follow:
- Task-related: reaction time and error rate during the task performance.
- MEG signal: scalp and source coherence between cortical regions, amplitude and latency of event-related potentials and even-related (de)synchronization.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01006109
|United States, Maryland|
|National Institutes of Health Clinical Center, 9000 Rockville Pike|
|Bethesda, Maryland, United States, 20892|
|Principal Investigator:||Mark Hallett, M.D.||National Institute of Neurological Disorders and Stroke (NINDS)|