Abstract：
It is generally believed that working memory (WM) is dysfunctional in depression. However, whether this impaired performance originates from impaired encoding, maintenance or both stages is still unclear. Here, we aimed to decompose the abnormal characteristics of encoding and maintenance in patients with recurrent major depressive disorder (MDD). Thirty patients and thirty-nine healthy controls completed a spatial working memory task where the encoding time and the retention time could vary under different load levels. Encoding performance was assessed by comparing accuracies between short and long encoding times, and maintenance performance was assessed by comparing accuracies between short and long retention times. The results show a lower performance in depression than the controls. However, while the decreased accuracy by long retention (vs. short retention) was increased by a short encoding time in the control group, the retention performance of the depression group did not further suffer from the short encoding time. The generally impaired encoding, together with limited maintenance of immunity against the constrained encoding time, suggests a common bias for fixed internal processing over external processing in recurrent MDD. The paradigm provided in this study can be a convenient and efficient clinical test for assessing the WM encoding and maintenance function.
摘要：
一般认为，工作记忆（WM）在抑郁症中是功能失调的。然而,这种受损的性能是否源于受损的编码，维护或两个阶段仍不清楚。这里,我们旨在分解复发性重度抑郁障碍（MDD）患者的编码和维持异常特征。30名患者和39名健康对照完成了空间工作记忆任务，其中编码时间和保留时间在不同的负荷水平下可能会有所不同。通过比较短编码时间和长编码时间之间的准确性来评估编码性能，通过比较短期和长期保留时间之间的准确性来评估维护性能。结果显示抑郁症的表现低于对照。然而,而长时间保留会降低精度(vs.短保留)在对照组中增加了短编码时间，抑郁组的保留性能没有进一步受到短编码时间的影响。通常受损的编码，加上对受限编码时间的有限免疫维护，表明在复发性MDD中，固定内部处理相对于外部处理存在共同偏差。本研究中提供的范例可以是评估WM编码和维护功能的方便有效的临床测试。
