Anderson Brian A, Kuwabara Hiroto, Wong Dean F, Courtney Susan M
Department of Psychology, Texas A&M University, College Station, Texas;
Section of High Resolution Brain PET, Division of Nuclear Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.
J Neurophysiol. 2017 Jul 1;118(1):64-68. doi: 10.1152/jn.00125.2017. Epub 2017 Mar 29.
The density (measured at binding potential) of available striatal D/D receptors has been shown to predict trait impulsiveness. This relationship is highly robust and well replicated. In each case, however, the availability of dopamine receptors was measured at rest. More broadly, the extent to which relationships between dopamine receptor availability and behavioral traits hold when participants perform a cognitive task is unclear. Furthermore, the performance of a cognitive task engages fundamentally different neural networks than are maximally engaged during the resting state. This complicates interpretation of previously observed correlations, which could be influenced by two distinct factors. The first is variation in available receptor density, which reflects a stable trait of the individual. The second is variation in context-specific dopamine release, which differentially displaces some dopamine radiotracers (such as raclopride) across individuals. Using an existing data set, we related trait impulsiveness, as measured using the Barratt Impulsiveness Scale (BIS-11), to the density (binding potential) of available striatal D/D receptors as measured using positron emission tomography (PET) with [C]raclopride. Importantly, the PET scan was completed while participants performed an attention-demanding visual search task. We replicate robust correlations between this measure of receptor availability and trait impulsiveness previously demonstrated during the resting state, extending this relationship to periods of active task engagement. Our results support the idea that this relationship depends on striatal D/D receptor density and not on context-dependent dopamine release. Several studies have demonstrated a relationship between the density of available striatal D/D receptors and trait impulsiveness. However, in each case, the availability of dopamine receptors was measured during the resting state. This complicates interpretation of previously observed correlations, which could be influenced by either stable variation in receptor density or context-dependent dopamine release. We present evidence uniquely consistent with the former interpretation, providing clarity to the nature of this brain-behavior relationship.
已证明，可用纹状体D/D受体的密度（在结合电位下测量）可预测特质冲动性。这种关系非常稳健且得到了充分的重复验证。然而，在每种情况下，多巴胺受体的可用性都是在静息状态下测量的。更广泛地说，当参与者执行认知任务时，多巴胺受体可用性与行为特质之间的关系在多大程度上成立尚不清楚。此外，认知任务的执行所涉及的神经网络与静息状态下最大程度参与的神经网络根本不同。这使得对先前观察到的相关性的解释变得复杂，因为这些相关性可能受到两个不同因素的影响。第一个因素是可用受体密度的变化，它反映了个体的稳定特质。第二个因素是特定情境下多巴胺释放的变化，它会使一些多巴胺放射性示踪剂（如雷氯必利）在个体间发生不同程度的置换。我们利用一个现有的数据集，将使用巴拉特冲动性量表（BIS-11）测量的特质冲动性与使用正电子发射断层扫描（PET）结合[C]雷氯必利测量的可用纹状体D/D受体的密度（结合电位）联系起来。重要的是，PET扫描是在参与者执行一项需要注意力的视觉搜索任务时完成的。我们重复验证了先前在静息状态下证明的这种受体可用性测量与特质冲动性之间的稳健相关性，并将这种关系扩展到了积极的任务参与期间。我们的结果支持这样一种观点，即这种关系取决于纹状体D/D受体密度，而不是取决于情境依赖性多巴胺释放。几项研究已经证明了可用纹状体D/D受体密度与特质冲动性之间的关系。然而，在每种情况下，多巴胺受体的可用性都是在静息状态下测量的。这使得对先前观察到的相关性的解释变得复杂，因为这些相关性可能受到受体密度的稳定变化或情境依赖性多巴胺释放的影响。我们提供的证据唯一地与前一种解释一致，从而明确了这种脑-行为关系的本质。
