Department of Psychology and Neuroscience, University of North Carolina-Chapel Hill, Chapel Hill, NC, United States.
Department of Psychiatry, University of North Carolina-Chapel Hill, Chapel Hill, NC, United States.
Psychiatry Res Neuroimaging. 2023 Aug;333:111660. doi: 10.1016/j.pscychresns.2023.111660. Epub 2023 Jun 1.
Anhedonia is hypothesized to be associated with blunted mesocorticolimbic dopamine (DA) functioning in samples with major depressive disorder. The purpose of this study was to examine linkages between striatal DA, reward circuitry functioning, anhedonia, and, in an exploratory fashion, self-reported stress, in a transdiagnostic anhedonic sample.
Participants with (n = 25) and without (n = 12) clinically impairing anhedonia completed a reward-processing task during simultaneous positron emission tomography and magnetic resonance (PET-MR) imaging with [C]raclopride, a DA D2/D3 receptor antagonist that selectively binds to striatal DA receptors.
Relative to controls, the anhedonia group exhibited decreased task-related DA release in the left putamen, caudate, and nucleus accumbens and right putamen and pallidum. There were no group differences in task-related brain activation (fMRI) during reward processing after correcting for multiple comparisons. General functional connectivity (GFC) findings revealed blunted fMRI connectivity between PET-derived striatal seeds and target regions in the anhedonia group. Associations were identified between anhedonia severity and the magnitude of task-related DA release to rewards in the left putamen, but not mesocorticolimbic GFC.
Results provide evidence for reduced striatal DA functioning during reward processing and blunted mesocorticolimbic network functional connectivity in a transdiagnostic sample with clinically significant anhedonia.
在伴有重度抑郁症的样本中，快感缺失被假设与中脑边缘多巴胺（DA）功能迟钝有关。本研究的目的是在一个跨诊断快感缺失样本中，检验纹状体 DA、奖励回路功能、快感缺失之间的联系，并以探索性方式检验自我报告的压力。
有（n=25）和没有（n=12）临床显著快感缺失的参与者在正电子发射断层扫描和磁共振（PET-MR）成像同时完成奖励处理任务，使用[C]raclopride，一种 DA D2/D3 受体拮抗剂，它选择性地与纹状体 DA 受体结合。
与对照组相比，快感缺失组在左壳核、尾状核和伏隔核以及右壳核和苍白球中观察到与任务相关的 DA 释放减少。在对多次比较进行校正后，奖励处理过程中与任务相关的大脑激活（fMRI）没有组间差异。一般功能连接（GFC）发现快感缺失组 PET 衍生纹状体种子与目标区域之间的 fMRI 连接减弱。在快感缺失严重程度与左壳核与任务相关的 DA 释放量之间存在关联，但与中脑边缘 GFC 无关。
结果提供了证据，表明在一个伴有临床显著快感缺失的跨诊断样本中，奖励处理过程中纹状体 DA 功能降低，中脑边缘网络功能连接减弱。
