Smoski Moria J, Felder Jennifer, Bizzell Joshua, Green Steven R, Ernst Monique, Lynch Thomas R, Dichter Gabriel S
Department of Psychiatry, Duke University Medical Center, Durham, NC, 27710, USA.
J Affect Disord. 2009 Nov;118(1-3):69-78. doi: 10.1016/j.jad.2009.01.034. Epub 2009 Mar 3.
The purpose of the present investigation was to evaluate reward processing in unipolar major depressive disorder (MDD). Specifically, we investigated whether adults with MDD demonstrated hyporesponsivity in striatal brain regions and/or hyperresponsivity in cortical brain regions involved in conflict monitoring using a Wheel of Fortune task designed to probe responses during reward selection, reward anticipation, and reward feedback. Functional magnetic resonance imaging (fMRI) data indicated that the MDD group was characterized by reduced activation of striatal reward regions during reward selection, reward anticipation, and reward feedback, supporting previous data indicating hyporesponsivity of reward systems in MDD. Support was not found for hyperresponsivity of cognitive control regions during reward selection or reward anticipation. Instead, MDD participants showed hyperresponsivity in orbitofrontal cortex, a region associated with assessment of risk and reward, during reward selection, as well as decreased activation of the middle frontal gyrus and the rostral cingulate gyrus during reward selection and anticipation. Finally, depression severity was predicted by activation in bilateral midfrontal gyrus during reward selection. Results indicate that MDD is characterized by striatal hyporesponsivity, and that future studies of MDD treatments that seek to improve responses to rewarding stimuli should assess striatal functioning.
本研究的目的是评估单相重度抑郁症(MDD)中的奖赏处理过程。具体而言,我们使用一个“财富之轮”任务来探究在奖赏选择、奖赏预期和奖赏反馈过程中的反应,该任务旨在探测参与冲突监测的纹状体脑区的低反应性和/或皮质脑区的高反应性,我们调查了患有MDD的成年人是否存在这些情况。功能磁共振成像(fMRI)数据表明,MDD组的特征是在奖赏选择、奖赏预期和奖赏反馈过程中纹状体奖赏区域的激活减少,这支持了先前表明MDD奖赏系统存在低反应性的数据。在奖赏选择或奖赏预期过程中,未发现认知控制区域存在高反应性。相反,MDD参与者在奖赏选择过程中,眶额皮质(一个与风险和奖赏评估相关的区域)表现出高反应性,并且在奖赏选择和预期过程中,额中回和喙扣带回的激活减少。最后,奖赏选择过程中双侧额中回的激活可预测抑郁严重程度。结果表明,MDD的特征是纹状体低反应性,并且未来旨在改善对奖赏刺激反应的MDD治疗研究应评估纹状体功能。