title: Functional activation and effective connectivity differences in adolescent marijuana users performing a simulated gambling task.
abstract: Background. Adolescent marijuana use is associated with structural and functional differences in forebrain regions while 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, these results indicate adolescent marijuana users have enhanced neural responses to simulated monetary rewards and losses and relatively subtle differences in effective connectivity.
authors.affiliation: Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA ; Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
authors.forename: Ashley
authors.identifier: 0000-0002-3843-5726
authors.initials: A
authors.lastname: Acheson
authors.affiliation: Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
authors.forename: Kimberly L
authors.initials: KL
authors.lastname: Ray
authors.affiliation: Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA ; The Audie Murphy VA Medical Center, San Antonio, TX 78229, USA.
authors.forename: Christina S
authors.initials: CS
authors.lastname: Hines
authors.affiliation: Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Dawes
authors.affiliation: Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Mathias
authors.affiliation: Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Dougherty
authors.affiliation: Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA ; Department of Physics, Florida International University, Miami, FL 33174, USA.
authors.forename: Angela R
authors.initials: AR
authors.lastname: Laird