In this project, we will examine effects of MA on reward function using electroencephalograms (EEG), which will complement our ongoing study with MA and fMRI. We will determine how MA alters reward-related neural activity and how this is related to its subjective rewarding effects. The effects of MA on reward function will be examined using both reward-task-related activation and resting state activity. We will examine the effects of MA on ratings of drug liking and euphoria, as well as on EEG measures sensitivity to reward. Healthy young adults will undergo three EEG sessions with placebo and MA (10 and 20 mg), while performing the Monetary Incentive Delay task and the Stop Task, as a measure of inhibition. We will examine correlations between the neural responses and subjective responses to MA.

Our central hypotheses are 1) that MA will increase feelings of alertness and well-being, and 2) that MA will increase neural responses to anticipation and receipt of reward, and 3) that the effects of MA on mood will be correlated with its effects on neural responses to reward.

Inclusion Criteria:

BMI between 19 and 26 Less than 4 alcohol or caffeinated beverages a day.

Exclusion Criteria:

High blood pressure

Any medical condition requiring regular medication Individuals with a current (within the last year) DSM-IV Axis 1 diagnosis Individuals with a history of dependence on stimulant drugs Women who are pregnant or trying to become pregnant.