Developmental imaging genetics: Linking dopamine function to adolescent behavior

Adolescence is a period of development characterized by numerous neurobiological changes that significantly influence behavior and brain function. Adolescence is of particular interest due to the alarming statistics indicating that mortality rates increase two to three-fold during this time compared to childhood, due largely to a peak in risk-taking behaviors resulting from increased impulsivity and sensation seeking. Furthermore, there exists large unexplained variability in these behaviors that are in part mediated by biological factors. Recent advances in molecular genetics and functional neuroimaging have provided a unique and exciting opportunity to non-invasively study the influence of genetic factors on brain function in humans. While genes do not code for specific behaviors, they do determine the structure and function of proteins that are essential to the neuronal processes that underlie behavior. Therefore, studying the interaction of genotype with measures of brain function over development could shed light on critical time points when biologically mediated individual differences in complex behaviors emerge. Here we review animal and human literature examining the neurobiological basis of adolescent development related to dopamine neurotransmission. Dopamine is of critical importance because of (1) its role in cognitive and affective behaviors, (2) its role in the pathogenesis of major psychopathology, and (3) the protracted development of dopamine signaling pathways over adolescence. We will then focus on current research examining the role of dopamine-related genes on brain function. We propose the use of imaging genetics to examine the influence of genetically mediated dopamine variability on brain function during adolescence, keeping in mind the limitations of this approach.     

道德的轻与重：道德的重量具身效应及隐喻的调节作用

本研究采用行为反应时和事件相关电位(ERP)探讨道德的重量具身效应及“重量-道德”隐喻联结对该效应的调节作用。参考内隐联想测验的逻辑，采用联合分类反应任务，在默认的“重量-道德”隐喻表征情境（实验1）和道德垂直空间隐喻的启动情境（实验2）中，要求被试分别使用轻鼠标和重鼠标对道德/不道德词进行分类判断，考察鼠标重量对道德概念的加工所产生的影响。结果显示，在默认情境中，“重-道德，轻-不道德”的联合分类条件比“轻-道德，重-不道德”条件的分类反应时更短，并伴随有更大的脑电晚期正成分（LPC），而在启动道德垂直空间隐喻后，两种联合分类条件下的反应时和LPC结果出现反转。本研究结果表明道德概念的加工会受到重量经验的影响，“重量-道德”具身效应具有心理现实性，且重量概念与道德概念的隐喻联结引导并调节了这种具身效应。