Medicine and Health Sciences Commons^™

Expectation Modulates Human Brain Responses To Acute Cocaine: A Functional Magnetic Resonance Imaging Study, Peter Kufahl, Zhu Li, Robert C. Risinger, Charles Rainey, Linda B. Piacentine, Gaohong Wu, Alan S. Bloom, Zheng Yang, Shi-Jiang Li

College of Nursing Faculty Research and Publications

Background

Human expectation of psychoactive drugs significantly alters drug effects and behavioral responses. However, their neurophysiological mechanisms are not clear. This study investigates how cocaine expectation modulates human brain responses to acute cocaine administration.

Methods

Twenty-six right-handed non–treatment-seeking regular cocaine abusers participated in this study. Changes in blood oxygenation level-dependent (BOLD) signals were measured, and online behavioral ratings during cocaine expectation and acute cocaine administration were recorded.

Results

Distinct regional characteristics in BOLD responses to expected and unexpected cocaine infusions were observed in the medial orbitofrontal gyrus (Brodmann area [BA] 11), frontal pole (BA 10), and anterior cingulate gyrus regions. …

Peripheral Blood Pressure Changes Induced By Dobutamine Do Not Alter Bold Signals In The Human Brain, Heng Liu, Charles Rainey, Kathryn K. Lauer, Linda B. Piacentine, Alan S. Bloom, Robert C. Risinger, B. Douglas Ward, Elliot Stein, Shi-Jiang Li

College of Nursing Faculty Research and Publications

In extending the use of functional MRI to neuropharmacology, a primary area of concern is that peripheral blood pressure changes induced by pharmacological agents could independently produce a change in the blood oxygenation level-dependent (BOLD) signal, resulting in difficulties distinguishing or interpreting drug-induced neural activations. In the present study, we utilized intravenous dobutamine, a beta-adrenergic receptor agonist, to increase the mean arterial blood pressure (MABP), while examining the effects of MABP changes on the BOLD signal in cocaine-dependent participants. Dobutamine infusion significantly increased the MABP from 93 ± 8 mm Hg to 106 ± 12 mm Hg (P < 0.0005), but did not produce a significant global BOLD signal. Yet, a few voxels in the anterior cingulate showed BOLD signal changes that paralleled the changes in blood pressure (BP). Our observations support the conclusion that following the infusion of psychoactive agents, brain BOLD signals accurately reflect neuronal activity, even in the face of relatively large peripheral cardiovascular effects that transiently increase systemic BP.