Developmental Neuroscience
2012
John C Churchwell, Paul D Carey, Helen L Ferrett et al.
It has been hypothesized that changes in striatal-mediated dopamine modulation during adolescence may increase the risk for initiating substance abuse as a result of its fundamental role in arbitrating reward sensitivity and motivation during learning and decision making. However, substance abuse during adolescence may also significantly modify striatal structure and function and concomitantly...
Neuroimage
July 1, 2011
Andrew P Prescot, Allison E Locatelli, Perry F Renshaw et al.
Converging evidence from neuroimaging and neuropsychological studies indicates that heavy marijuana use is associated with cingulate dysfunction. However, there has been limited human data documenting in vivo biochemical brain changes after chronic marijuana exposure. Previous proton magnetic resonance spectroscopy studies have demonstrated reduced basal ganglia glutamate and dorsolateral...
Behavioural Brain Research
June 20, 2011
Melissa P Lopez-Larson, Piotr Bogorodzki, Jadwiga Rogowska et al.
There are limited data regarding the impact of marijuana (MJ) on cortical development during adolescence. Adolescence is a period of substantial brain maturation and cortical thickness abnormalities may be indicative of disruptions of normal cortical development. This investigation applied cortical-surface based techniques to compare cortical thickness measures in MJ using adolescents compared...
Experimental and Clinical Psychopharmacology
June 2011
Staci A Gruber, Marisa M Silveri, Mary Kathryn Dahlgren et al.
Difficulty monitoring and inhibiting impulsive behaviors has been reported in marijuana (MJ) smokers; neuroimaging studies, which examined frontal systems in chronic MJ smokers, have reported alterations during inhibitory tasks. Diffusion tensor imaging (DTI) provides a quantitative estimate of white matter integrity at the microstructural level. We applied DTI, clinical ratings, and...
Frontiers in Psychology
2010
John C Churchwell, Melissa P Lopez-Larson, Deborah A Yurgelun-Todd
Anticipating future outcomes is central to decision making and a failure to consider long-term consequences may lead to impulsive choices. Adolescence is a vulnerable period during which underdeveloped prefrontal cortical systems may contribute to poor judgment, impulsive choices, and substance abuse. Conversely, substance abuse during this period may alter neural systems involved in decision...
Drug and Alcohol Dependence
November 1, 2009
Staci A Gruber, Jadwiga Rogowska, Deborah A Yurgelun-Todd
More than 94 million Americans have tried marijuana, and it remains the most widely used illicit drug in the nation. Investigations of the cognitive effects of marijuana report alterations in brain function during tasks requiring executive control, including inhibition and decision-making. Endogenous cannabinoids regulate a variety of emotional responses, including anxiety, mood control, and...
Experimental and Clinical Psychopharmacology
November 2006
Jennifer T Sneider, Harrison G. Pope, Marisa M Silveri et al.
The quantitative measurement of cerebral perfusion is crucial for the study of both normal and impaired human brain function. Although cannabis is the most commonly abused illicit substance in the United States, its effects on cerebral blood volume (CBV) have not been fully examined. The objective of the present study was to examine differences in relative regional blood volume in focal regions...
Biological Psychiatry
October 15, 2005
John H. Halpern, Andrea R Sherwood, James I. Hudson et al.
186 citations
Hallucinogens are widely used, both by drug abusers and by peoples of traditional cultures who ingest these substances for religious or healing purposes. However, the long-term residual psychological and cognitive effects of hallucinogens remain poorly understood. We recruited three groups of Navajo Native Americans, age 18-45: 1) 61 Native American Church members who regularly ingested peyote,...
Brain research. Cognitive brain research
April 2005
Staci A Gruber, Deborah A Yurgelun-Todd
Neuropsychological investigations of substance abusers have reported impairments on tasks mediated by the frontal executive system, including functions associated with behavioral inhibition and decision making. The higher order or executive components which are involved in decision making include selective attention and short term storage of information, inhibition of response to irrelevant...
Drug and Alcohol Dependence
August 16, 2004
John H. Halpern, Harrison G. Pope, Andrea R Sherwood et al.
A substantial literature suggests that users of illicit 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") display residual cognitive deficits. Most MDMA users, however, use other illicit drugs as well, so it is difficult to be certain that these deficits are due to MDMA, as opposed to other drug use or additional confounding factors. We administered a battery of neuropsychological tests to...