Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institute of Health, Baltimore, Maryland (I.F., M.V., D.J.R., J.J.C., J.M.B., Y.S.), and Center for Social and Affective Neuroscience, Linköping University, Linköping, Sweden

Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institute of Health, Baltimore, Maryland (I.F., M.V., D.J.R., J.J.C., J.M.B., Y.S.), and Center for Social and Affective Neuroscience, Linköping University, Linköping, Sweden

Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institute of Health, Baltimore, Maryland (I.F., M.V., D.J.R., J.J.C., J.M.B., Y.S.), and Center for Social and Affective Neuroscience, Linköping University, Linköping, Sweden

Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institute of Health, Baltimore, Maryland (I.F., M.V., D.J.R., J.J.C., J.M.B., Y.S.), and Center for Social and Affective Neuroscience, Linköping University, Linköping, Sweden

Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institute of Health, Baltimore, Maryland (I.F., M.V., D.J.R., J.J.C., J.M.B., Y.S.), and Center for Social and Affective Neuroscience, Linköping University, Linköping, Sweden

Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institute of Health, Baltimore, Maryland (I.F., M.V., D.J.R., J.J.C., J.M.B., Y.S.), and Center for Social and Affective Neuroscience, Linköping University, Linköping, Sweden