Psychobiology Section (R.I.D., J.L.K.) and Electrophysiology Research Section (C.R.L.), National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland; and Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon (D.K.G.)

Psychobiology Section (R.I.D., J.L.K.) and Electrophysiology Research Section (C.R.L.), National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland; and Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon (D.K.G.)

Psychobiology Section (R.I.D., J.L.K.) and Electrophysiology Research Section (C.R.L.), National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland; and Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon (D.K.G.)

Psychobiology Section (R.I.D., J.L.K.) and Electrophysiology Research Section (C.R.L.), National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland; and Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon (D.K.G.)