Stedron Jennifer Merva, Sahni Sarah Devi, Munakata Yuko
University of Denver, USA.
J Cogn Neurosci. 2005 Apr;17(4):623-31. doi: 10.1162/0898929053467622.
Everyone perseverates at one time or another, repeating previous behaviors when they are no longer appropriate. Such perseveration often occurs in situations with working memory demands, and the ability to overcome perseveration has been linked to brain regions critical for working memory. Many theories thus explain perseveration in terms of working memory deficits. However, perseveration also occurs in situations without apparent working memory demands, in which the visible environment specifies appropriate behavior. Such findings appear to challenge working memory accounts of perseveration. To evaluate this challenge, a neural network model of a working memory account of perseveration was tested on tasks with visible solutions. With advances in the mechanisms that support working memory, networks became increasingly able to attend to relevant information in the environment. These developments led to improvements in performance on tasks with visible solutions, paralleling the developmental progression observed in infants. The simulations demonstrate how mechanisms of working memory can subserve perseveration and success on tasks with and without obvious memory demands. In both types of tasks, controlled processing occurs through the activation of task-relevant representations, which provide top-down biasing of other processing pathways. More generally, the simulations demonstrate how common mechanisms can support working memory and attention.
每个人都会在某个时候出现持续重复行为，即在行为不再合适时仍重复先前的行为。这种持续重复行为常在有工作记忆要求的情况下发生，而克服持续重复行为的能力与对工作记忆至关重要的脑区有关。因此，许多理论从工作记忆缺陷的角度来解释持续重复行为。然而，持续重复行为也会在没有明显工作记忆要求的情况下出现，在这种情况下，可见环境会明确适当的行为。这些发现似乎对用工作记忆来解释持续重复行为的观点提出了挑战。为了评估这一挑战，一个关于持续重复行为的工作记忆解释的神经网络模型在有可见解决方案的任务上进行了测试。随着支持工作记忆的机制的进步，网络越来越能够关注环境中的相关信息。这些进展导致在有可见解决方案的任务上的表现得到改善，这与在婴儿身上观察到的发展进程相似。模拟结果表明了工作记忆机制如何在有和没有明显记忆要求的任务中促进持续重复行为和成功完成任务。在这两种类型的任务中，控制性加工通过激活与任务相关的表征来发生，这些表征为其他加工途径提供自上而下的偏向。更普遍地说，模拟结果表明了共同机制如何支持工作记忆和注意力。
