Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland.
Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland.
Biol Psychiatry Cogn Neurosci Neuroimaging. 2020 Sep;5(9):913-922. doi: 10.1016/j.bpsc.2020.05.003. Epub 2020 May 19.
Impairments in spatial working memory (sWM) have been well documented in schizophrenia. Here we provide a comprehensive test of a microcircuit model of WM performance in schizophrenia that predicts enhanced effects of increasing delay duration and distractors based on a hypothesized imbalance of excitatory and inhibitory processes.
Model predictions were tested in 41 people with schizophrenia (PSZ) and 32 healthy control subjects (HCS) performing an sWM task. In one condition, a single target location was followed by delays of 0, 2, 4, or 8 seconds. In a second condition, distractors were presented during the 4-second delay interval at 20°, 30°, 40°, 50°, or 90° from the original target location.
PSZ showed less precise sWM representations than HCS, and the rate of memory drift over time was greater in PSZ than in HCS. Relative to HCS, the spatial recall responses of PSZ were more repelled by distractors presented close to the target location and more attracted by distractors presented far from the target location. The degree of attraction to distant distractors was correlated with the rate of memory drift in the absence of distractors.
Consistent with the microcircuit model, PSZ exhibited both a greater rate of drift and greater attraction to distant distractors relative to HCS. These two effects were correlated, consistent with the proposal that they arise from a single underlying mechanism. However, the repulsion effects produced by nearby distractors were not predicted by the model and thus require an updated modeling framework.
精神分裂症患者的空间工作记忆（sWM）损伤已得到充分证实。在这里，我们提供了一个 WM 性能的微电路模型的综合测试，该模型基于兴奋和抑制过程失衡的假设，预测了增加延迟持续时间和分心物的增强效应。
在执行 sWM 任务时，我们对 41 名精神分裂症患者（PSZ）和 32 名健康对照者（HCS）进行了模型预测。在一种情况下，只有一个目标位置，然后是 0、2、4 或 8 秒的延迟。在第二种情况下，在 4 秒的延迟间隔内，在距离原始目标位置 20°、30°、40°、50°或 90°的地方呈现分心物。
PSZ 的 sWM 表示比 HCS 更不精确，并且 PSZ 的记忆漂移率高于 HCS。与 HCS 相比，PSZ 的空间回忆反应受到靠近目标位置呈现的分心物的排斥作用更大，受到远离目标位置呈现的分心物的吸引作用更大。对远距离分心物的吸引力与无分心物时的记忆漂移率相关。
与微电路模型一致，PSZ 表现出比 HCS 更大的漂移率和对远距离分心物的更大吸引力。这两个效应是相关的，这与它们来自单一潜在机制的假设一致。然而，模型并未预测到附近分心物产生的排斥效应，因此需要一个更新的建模框架。
