有兴奋剂依赖风险的年轻成年人对风险的神经处理减弱。
Attenuated Neural Processing of Risk in Young Adults at Risk for Stimulant Dependence.
作者信息
Reske Martina, Stewart Jennifer L, Flagan Taru M, Paulus Martin P
机构信息
Department of Psychiatry, University of California San Diego, La Jolla, California, United States of America; Institute of Neuroscience and Medicine (INM-6), Computational and Systems Neuroscience and Institute for Advanced Simulation (IAS-6), Theoretical Neuroscience, Forschungszentrum Jülich GmbH, Jülich, Germany; JARA BRAIN Institute I, Jülich, Germany.
Department of Psychiatry, University of California San Diego, La Jolla, California, United States of America; CUNY Queens College, Queens, New York, United States of America.
出版信息
PLoS One. 2015 Jun 15;10(6):e0127010. doi: 10.1371/journal.pone.0127010. eCollection 2015.
OBJECTIVE
Approximately 10% of young adults report non-medical use of stimulants (cocaine, amphetamine, methylphenidate), which puts them at risk for the development of dependence. This fMRI study investigates whether subjects at early stages of stimulant use show altered decision making processing.
METHODS
158 occasional stimulants users (OSU) and 50 comparison subjects (CS) performed a "risky gains" decision making task during which they could select safe options (cash in 20 cents) or gamble them for double or nothing in two consecutive gambles (win or lose 40 or 80 cents, "risky decisions"). The primary analysis focused on risky versus safe decisions. Three secondary analyses were conducted: First, a robust regression examined the effect of lifetime exposure to stimulants and marijuana; second, subgroups of OSU with >1000 (n = 42), or <50 lifetime marijuana uses (n = 32), were compared to CS with <50 lifetime uses (n = 46) to examine potential marijuana effects; third, brain activation associated with behavioral adjustment following monetary losses was probed.
RESULTS
There were no behavioral differences between groups. OSU showed attenuated activation across risky and safe decisions in prefrontal cortex, insula, and dorsal striatum, exhibited lower anterior cingulate cortex (ACC) and dorsal striatum activation for risky decisions and greater inferior frontal gyrus activation for safe decisions. Those OSU with relatively more stimulant use showed greater dorsal ACC and posterior insula attenuation. In comparison, greater lifetime marijuana use was associated with less neural differentiation between risky and safe decisions. OSU who chose more safe responses after losses exhibited similarities with CS relative to those preferring risky options.
DISCUSSION
Individuals at risk for the development of stimulant use disorders presented less differentiated neural processing of risky and safe options. Specifically, OSU show attenuated brain response in regions critical for performance monitoring, reward processing and interoceptive awareness. Marijuana had additive effects by diminishing neural risk differentiation.
目的
约10%的年轻人报告有非医疗目的使用兴奋剂（可卡因、苯丙胺、哌甲酯）的情况，这使他们面临成瘾的风险。这项功能磁共振成像（fMRI）研究调查了处于兴奋剂使用早期阶段的受试者的决策过程是否发生改变。
方法
158名偶尔使用兴奋剂者（OSU）和50名对照受试者（CS）进行了一项“风险收益”决策任务，在此过程中，他们可以选择安全选项（获得20美分现金），或者在连续两次赌博中冒险将其翻倍或一无所获（赢或输40或80美分，“风险决策”）。主要分析集中在风险决策与安全决策上。进行了三项次要分析：第一，通过稳健回归研究终生接触兴奋剂和大麻的影响；第二，将终生使用兴奋剂超过1000次（n = 42）或终生使用大麻少于50次的OSU亚组与终生使用大麻少于50次的CS（n = 46）进行比较，以研究大麻的潜在影响；第三，探究与金钱损失后行为调整相关的脑激活情况。
结果
两组之间在行为上没有差异。OSU在额叶前皮质（前额叶皮质）、脑岛和背侧纹状体的风险决策和安全决策中均表现出激活减弱，在风险决策中前扣带回皮质（ACC）和背侧纹状体激活较低，在安全决策中额下回激活较高。那些使用兴奋剂相对较多的OSU表现出背侧ACC和后岛叶的激活减弱更为明显。相比之下，终生使用大麻较多与风险决策和安全决策之间的神经分化较少有关。在损失后选择更多安全反应的OSU相对于那些偏好风险选项的OSU，与CS表现出相似性。
讨论
有发展为兴奋剂使用障碍风险的个体在风险选项和安全选项的神经加工上表现出较少的分化。具体而言，OSU在对绩效监测、奖励处理和内感受性意识至关重要的区域表现出脑反应减弱。大麻通过减少神经风险分化产生叠加效应。
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