Carlson Joshua M, Foti Dan, Harmon-Jones Eddie, Proudfit Greg H
Department of Psychology, Northern Michigan University, Marquette, MI, 49855, USA,
Brain Struct Funct. 2015;220(3):1861-6. doi: 10.1007/s00429-014-0725-9. Epub 2014 Feb 19.
Ventral striatal activation measured with functional magnetic resonance imaging (fMRI) and feedback negativity amplitude measured with event-related potentials (ERPs) are each enhanced during reward processing. Recent research has found that these two neural measures of reward processing are also related to one another, such that increases in ventral striatal activity are accompanied by increases in the amplitude of the feedback negativity. Although there is a long history of research implicating the midbrain dopamine system in reward processing, there has been little research into the possibility that structural variability in the midbrain may be linked to functional variability in reward reactivity. Here, we used structural MRI to measure midbrain volumes in addition to fMRI and ERP measures of functional neural reactivity to rewards in a simple gambling task. The results suggest that as midbrain volumes increase, fMRI reward reactivity in the ventral striatum and medial prefrontal cortex also increases. A similar relationship exists between midbrain structure and the amplitude of the feedback negativity; further, this relationship is mediated specifically by activity in the ventral striatum. These data demonstrate convergence between neuroanatomical, hemodynamic, and electrophysiological measures. Thus, structural variability in the midbrain relates to variability in fMRI and ERP measures of functional reward reactivity, which may play a critical role in reward-related psychopathologies and the treatment of these disorders.
通过功能磁共振成像（fMRI）测量的腹侧纹状体激活以及通过事件相关电位（ERP）测量的反馈负波幅度在奖励处理过程中均会增强。最近的研究发现，这两种奖励处理的神经测量方法也相互关联，即腹侧纹状体活动的增加伴随着反馈负波幅度的增加。尽管有很长的研究历史表明中脑多巴胺系统与奖励处理有关，但对于中脑结构变异性可能与奖励反应性的功能变异性相关这一可能性的研究却很少。在这里，我们除了在一个简单的赌博任务中使用fMRI和ERP测量对奖励的功能性神经反应外，还使用结构MRI测量中脑体积。结果表明，随着中脑体积的增加，腹侧纹状体和内侧前额叶皮质的fMRI奖励反应性也会增加。中脑结构与反馈负波幅度之间也存在类似的关系；此外，这种关系具体由腹侧纹状体的活动介导。这些数据证明了神经解剖学、血液动力学和电生理测量之间的趋同性。因此，中脑的结构变异性与fMRI和ERP测量的功能性奖励反应性的变异性有关，这可能在与奖励相关的精神病理学及其治疗中起关键作用。
