Research Article Functional Activation and Effective Connectivity Differences in Adolescent Marijuana Users Performing a Simulated Gambling Task

Copyright © 2015 Ashley Acheson et al.This is an open access article distributed under the Creative CommonsAttribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Adolescentmarijuana use is associatedwith structural and functional differences in forebrain regionswhile performing memory and attention tasks. In the present study, we investigated neural processing in adolescent marijuana users experiencing rewards and losses. Fourteen adolescents with frequent marijuana use (>5 uses per week) and 14 nonuser controls performed a computer task where they were required to guess the outcome of a simulated coin flip while undergoing magnetic resonance imaging. Results. Across all participants, “Wins ” and “Losses ” were associated with activations including cingulate, middle frontal, superior frontal, and inferior frontal gyri and declive activations. Relative to controls, users had greater activity in the middle and inferior frontal gyri, caudate, and claustrum during “Wins ” and greater activity in the anterior and posterior cingulate, middle frontal gyrus, insula, claustrum, and declive during “Losses. ” Effective connectivity analyses revealed similar overall network interactions among these regions for users and controls during both “Wins ” and “Losses. ” However, users and controls had significantly different causal interactions for 10 out of 28 individual paths during the “Losses ” condition. Conclusions. Collectively