Distinguishing bipolar disorder (BD) from major depressive disorder (MDD) is clinically challenging, especially during depressive episodes. While both groups are characterized by aberrant working memory and anticipatory processing, the role of these processes in discriminating BD from MDD remains unexplored. In this study, we examine how brain activation corresponding to anticipation of and performance on easy vs. difficult working memory tasks with emotional stimuli contributes to discrimination among BD, MDD, and healthy controls (HC). Depressed individuals with BD (n = 18), MDD (n = 23), and HC (n = 23) were scanned while performing a working memory task in which they had to first anticipate performance on 1-back (easy) or 2-back (difficult) tasks with happy, fearful, or neutral faces, and then, perform the task. Anticipation-related and task-related brain activation was measured in the whole brain using functional magnetic resonance imagining. We used an elastic-net regression for variable selection, and a random forest classifier for BD vs. MDD classification. The former selected the activation differences (1-back minus 2-back) in the lateral and medial prefrontal cortices (PFC) during task anticipation and performance on the working memory tasks with fearful and neutral faces as variables relevant for BD vs. MDD classification. BD vs. MDD were classified with 70.7% accuracy (p < 0.01) based on the neuroimaging measures alone, with 80.5% accuracy (p = 0.001) based on clinical measures alone, and with 85.4% accuracy (p < 0.001) based on clinical and neuroimaging measures together. These findings suggest that PFC activation during working memory task anticipation and performance may be an important biological marker distinguishing BD from MDD.

中文翻译：

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工作记忆任务预期期间前额皮质的激活有助于区分双相抑郁症和单相抑郁症。


区分双相情感障碍 (BD) 和重度抑郁症 (MDD) 在临床上具有挑战性，尤其是在抑郁发作期间。虽然这两个群体的特征都是异常的工作记忆和预期处理，但这些过程在区分 BD 和 MDD 中的作用仍有待探索。在这项研究中，我们研究了在情绪刺激下，与简单工作记忆任务和困难工作记忆任务的预期和表现相对应的大脑激活如何有助于区分 BD、MDD 和健康对照 (HC)。患有 BD (n = 18)、MDD (n = 23) 和 HC (n = 23) 的抑郁症患者在执行工作记忆任务时接受扫描，在该任务中，他们必须首先预测 1-back（简单）或 2-back（简单）的表现。带着快乐、恐惧或中性的表情返回（困难的）任务，然后执行任务。使用功能磁共振成像测量整个大脑中与预期相关和任务相关的大脑激活。我们使用弹性网络回归进行变量选择，并使用随机森林分类器进行 BD 与 MDD 分类。前者选择在任务预期和执行带有恐惧和中性面孔的工作记忆任务期间外侧和内侧前额皮质（PFC）的激活差异（1-back减去2-back）作为BD与MDD分类的相关变量。仅基于神经影像学测量，BD 与 MDD 的分类准确度为 70.7% (p < 0.01)，仅基于临床测量的准确度为 80.5% (p = 0.001)，基于临床测量的准确度为 85.4% (p < 0.001)。结合临床和神经影像学测量。这些发现表明，工作记忆任务预期和执行过程中 PFC 的激活可能是区分 BD 和 MDD 的重要生物标志物。