BRAIN DEVELOPMENT OF ADOLESCENT MARIJUANA USERS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 这项研究将研究首次使用大麻的年龄和使用时间对大脑功能，大脑结构和认知的影响。 考虑到大麻是使用最广泛的非法药物，如果长期使用会使一些大麻使用者产生脑功能障碍，而这种功能障碍在青少年时期开始使用较早和使用时间较长的人中更严重，那么社会的潜在成本可能会很高。 使用正电子发射断层扫描和磁共振成像，我们将检查慢性大麻使用者和对照组之间的差异，在基线区域脑血流量和认知相关的变化，在区域脑血流量（在记忆，敲击和赌博测试），以及全脑血流量和脑组织的体积和组成。 我们假设慢性大麻使用者与对照受试者不同，并且这些差异在首次使用年龄较早和使用持续时间较长的大麻使用者中更加明显。 假设长期使用大麻对小脑后部、前额皮质和海马的局部脑血流的影响是拟议研究的特别焦点。 如果假设的影响发生，他们将提供证据表明，长期使用大麻会改变大脑功能，而通常在青春期发生的明显的大脑发育会增加对这种改变的脆弱性。 此外，更广泛的认知测试将在不涉及神经成像的会议中进行，以测试大麻使用的认知影响在首次使用年龄较早和使用时间较长的个体中也更明显的假设。 受试者组将使用标准化测试分数记录进行病前智力功能的匹配，这些标准化测试分数记录可用于爱荷华州几乎所有地区接受教育的儿童。 完成后，拟议中的研究将为有关长期使用大麻对人脑功能，大脑结构和认知的影响的知识提供重要补充。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This research will examine the effects of age of first use of marijuana and duration of use on brain function, brain structure, and cognition. Considering that marijuana is the most widely used illicit drug, if chronic use produces brain dysfunction in some marijuana users and this dysfunction is greater in those who begin use earlier during adolescence and use longer, the potential costs to society could be high. Using positron emission tomography and magnetic resonance imaging, we will examine differences between chronic marijuana users and control subjects in baseline regional cerebral blood flow and cognition-related changes in regional cerebral blood flow (in memory, tapping and gambling tests), as well as whole brain blood flow and brain tissue volume and composition. We hypothesize that chronic marijuana users will differ from control subjects and these differences will be more pronounced in marijuana users with earlier ages of first use and longer durations of use. Hypothesized effects of chronic marijuana use on regional cerebral blood flow in posterior cerebellum, prefrontal cortex, and hippocampus are particular foci of the proposed research. If the hypothesized effects occur, they will provide evidence that chronic marijuana use alters brain functioning and that the pronounced brain development that normally occurs during adolescence increases vulnerability to such alterations. Additional, more extensive cognitive tests will be administered in sessions not involving neuroimaging to test the hypothesis that cognitive effects of marijuana use are also more pronounced in individuals with earlier ages of first use and longer durations of use. Groups of subjects will be matched on premorbid intellectual function using records of standardized test scores that are available for children educated in virtually all parts of Iowa. When completed, the proposed research will make important additions to knowledge about effects of chronic marijuana use on human brain function, brain structure, and cognition.