Development and Validation of Learning and Decision-Making Tasks

Background:Substance use disorders (SUD) can be considered disorders in the way people process incentives, learn, and make decisions. To understand why some people develop SUD, researchers need to develop reliable tests that show how people think and learn. This natural history study seeks to develop a set of tasks that could then be used to test how people learn and make decisions.Objective:To develop and validate behavioral tasks that could be used in future studies.Eligibility:Healthy people aged 18-45 years from the Baltimore area. They must also be enrolled in protocol 06-DA-N415.Design:Participants will perform different tasks. Most tasks require 1-4 study visits; some may require up to 12. Visits are 1-14 days apart. All visits will last about 1-7 hours.Participants will perform tasks on a computer. As they work they may be given different stimuli:Smells. Participants will sniff odors through a plastic tube or mask on their nose.Flavors. Participants will wear a mouthpiece and small amounts of different flavored liquids will be placed in their mouth.Pictures. Participants will look at different images.Sounds. Participants will wear headphones and various sounds will be played for them.Food. Participants may be asked to eat a meal before, during, or after a task. The researchers will provide the meal.During each task, participants will wear sensors to monitor their heart rate, blood pressure, breathing, and other physical changes in their bodies.Some participants will have a functional magnetic resonance imaging (fMRI) scan. They will lie on a table that slides into a cylinder. They will perform tasks on a computer screen during the fMRI.

INCLUSION CRITERIA:There are two levels of inclusion and exclusion criteria; those applying to all participants and those applying to participants in the MRI phase only. Participants will be cleared for both the behavioral and MRI phases, if eligible, and will be invited to sign one or both consents depending on what tasks are active at the time of consent. If a person is not MRI compatible, they will only be offered enrollment into the behavioral phase of the study.In order to be eligible to participate in this study, an individual must meet the following criteria:Stated willingness to comply with all study procedures and availability for the duration of the study.Male or female, aged 18-45 years old. Justification: Many neural processes change with age, and these changes could introduce unwanted variability in both behavioral and MRI signals.In good general health as evidenced by Medical-History Questionnaire (MHQ).Agreement to adhere to Lifestyle Considerations throughout study durationIn order to be eligible to participate in the MRI phase of this study, an individual must - in addition - also meet all of the following criteria:Right-handed.EXCLUSION CRITERIA:Individuals who meet any of the following criteria will be excluded from participation:History of neurological illnesses or neurosurgery including but not limited to cardiovascular accident, Parkinson disease, Alzheimer disease, Huntington disease, CNS tumor, head trauma, multiple sclerosis or other demyelinating diseases, epilepsy, movement disorders.History of current (past 12 months) major DSM-5 psychiatric disorder including major affective disorder, obsessive-compulsive disorder, schizophrenia, SUD, and PTSD.Current use of psychoactive medications and medications that affect alertness and that cannot be withheld on the morning of the study visit.History of anaphylaxis, e.g., due to severe asthma or food and non-food allergies (e.g., latex, detergents, soap, etc.).Non-English speaking. Justification: To include non-English speakers, we would have to translate the consent and other study documents and hire and train bilingual staff, which would require resources that we do not have and could not justify, given the small sample size for each experiment. Additionally, the data integrity of some of the cognitive tasks used in this study would be compromised as they have only been validated in English. Most importantly, ongoing communication regarding safety procedures is necessary when participants are undergoing MRI procedures. The inability to effectively communicate MRI safety procedures in a language other than English could compromise the safety of non-English speaking participants.Pregnancy.Any other condition that in the judgment of the investigators is incompatible with participation.An individual who meets any of the following criteria will be excluded from participation in the MRI phase of this study:Unable to undergo MRI scanning due to certain metallic or magnetic devices or implants in the body, claustrophobia or body morphometry.