MRS/fMRI Investigations of Adolescent Cannabis Use

我们提出的研究的总体目标是检查大麻对发展的影响， 吸食大麻青少年和健康非吸食者额叶系统及其功能的研究 青少年通过应用一套互补的磁共振（MR）技术， 神经心理学评估我们之前的研究已经发现了与年龄相关的差异 在健康青少年的认知、形态测量和功能磁共振成像（fMRI）方面。 此外，我们还发现了大麻使用的早期发作和贫穷之间的联系。 神经心理学表现，以及前扣带回和 背外侧前额叶皮层对运动和记忆功能的措施后不久停止， 成人使用大麻因此，我们建议研究大麻发病年龄的影响 在两个青少年队列中使用：1）14岁队列，报告至少100次使用 大麻;和2）一个18岁的队列谁报告了相同数量的大麻使用，但谁做了 直到16岁生日后才开始吸烟。两组都将与年龄匹配的非- 吸烟青少年尽管有大量证据表明 吸食大麻和额叶执行功能改变之间的关系，一直很难研究， 记录与大麻有关的人类大脑功能变化，特别是在青春期。 在这个建议中，我们将利用高空间分辨率和增加的信噪比 提供了互补的高场MR技术，以研究化学和功能的影响， 大麻使用在额叶大脑区域，已知经历成熟的完善， 青春期具体而言，本研究将采用局灶性功能MR BOLD技术， 在3特斯拉的认知和情感挑战范例，和单体素GABA光谱的 扣带在4特斯拉，与执行功能的神经心理学措施，以解决 问题是，当大脑额叶区域处于发育阶段时， 是大麻使用的早期和晚期我们相信这些对大脑的测量 功能将为抑制性处理和决策的神经机制提供新的见解- 在滥用大麻的青少年中，这对早期干预有影响， 补救措施

The overall aim of our proposed study is to examine the effects of marijuana on the development of frontal lobe systems and their function in marijuana-smoking adolescents and healthy non-using adolescents by applying a complementary set of magnetic resonance (MR) techniques and neuropsychological assessments. Our previous investigations have identified age-related differences in cognition, morphometry and functional magnetic resonance imaging (fMRI) in healthy adolescents. Furthermore, we have found an association between early onset of marijuana use and poorer neuropsychological performance, as well as abnormal cortical activation in the anterior cingulate and dorsal lateral prefrontal cortex on measures of motor and memory function shortly after cessation of marijuana use in adults. We therefore propose to examine the effects of age of onset of marijuana use in two adolescent cohorts: 1) a 14 year old cohort who report a minimum of 100 episodes of using marijuana; and 2) an 18 year old cohort who report the same amount of marijuana usage, but who did not begin smoking until after their 16thbirthday. Both groups will be compared to age matched non- smoking adolescents. Although significant evidence has accumulated indicating an association between marijuana use and altered frontal-executive function, it has been difficult to study and document functional human brain changes associated with marijuana, particularly during adolescence. In this proposal, we will take advantage of the high spatial resolution and increased signal to noise offered by complementary high field MR techniques to investigate chemical and functional effects of marijuana use in frontal brain regions that are known to undergo maturational refinements during adolescence. Specifically, this study will incorporate focal functional MR BOLD techniques using cognitive and affective challenge paradigms at 3 Tesla, and single voxel GABA spectroscopy of the cingulate at 4 Tesla, with neuropsychological measures of executive function, in order to address the question of whether developing frontal brain regions are more vulnerable to illicit drug use when there is an early versus late onset of marijuana use. We believe these complimentary measures of brain function will provide new insights into the neural mechanisms of inhibitory processing and decision- making in adolescents who abuse marijuana, which has implications for early intervention and remediation.