A computational approach to prefrontal cortex, cognitive control and schizophrenia: Recent developments and current challenges
A computational approach to prefrontal cortex, cognitive control and schizophrenia: Recent developments and current challenges
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DOI：
10.1098/rstb.1996.0138
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发表时间：
1996-10-29
影响因子：
6.3
通讯作者：
OReilly, RC
中科院分区：
文献类型：
--
作者：
Cohen, JD;Braver, TS;OReilly, RC
在这一章中，我们考虑认知控制的机制--从计算和神经生物学的角度--以及这些机制如何在精神分裂症中受损。我们所说的“控制”，指的是认知系统根据特定任务的要求灵活调整其行为的能力，它有利于处理与任务相关的信息，而不是其他相互竞争的信息来源，并调节与任务相关的行为，而不是习惯性的或其他优势反应。大量证据表明，前额叶皮质(PFC)在认知控制中起着关键作用。在之前的工作中，我们已经使用计算框架来理解和开发PFC的这一功能及其在精神分裂症中的损害的显式模型。这项工作导致了一种假设，即PFC包含了一种表示和维护上下文信息的机制。我们已经证明，这种机制可以解释通常归因于PFC的行为抑制和活跃记忆功能，以及人类在简单的注意、语言和记忆任务中的表现，这些任务利用这些功能进行认知控制。此外，我们还使用我们的模型模拟了在精神分裂症中观察到的认知缺陷的详细模式，精神分裂症是一种与认知控制明显障碍相关的疾病，也是一种公认的PFC缺陷。在这里，我们回顾了最近的实证研究的结果，这些研究测试了我们的模型在专门为探索背景处理而设计的任务中对精神分裂症表现的预测。这些结果表明，在任务条件下，选择性精神分裂症缺陷对记忆和抑制的要求最高，我们认为这两者都依赖于上下文的处理。此外，我们观察了首发患者和多发患者恶化的预测模式。我们还讨论了计算工作中的最新发展，这些发展导致了模型的改进，使我们能够模拟任务性能的更详细方面，例如反应时间数据和任务参数的操作，如刺激间延迟。这些改进的模型做出了几个具有挑衅性的新预测，包括精神分裂症患者和对照受试者预计将表现出类似的反应时表现的条件，我们提供了支持这些预测的初步数据。尽管取得了这些成功，但我们关于精神分裂症患者PFC功能及其损害的理论仍处于早期发展阶段。最后，我们提出了以目前的形式对该理论提出的一些挑战，以及我们已经开始采取的新方向来应对这些挑战。特别是，我们专注于关于PFC中主动维持表征的潜在机制的改进，以及这些表征的特征，这些表征允许它们支持正常人类行为所展示的认知控制的灵活性。总之，我们相信这项工作说明了计算方法对于理解认知控制的机制的价值，这些机制在神经和心理水平上都是负责的，以及它们在精神分裂症中的具体分解方式。
In this chapter we consider the mechanisms involved in cognitive control - from both a computational and a neurobiological perspective - and how these might be impaired in schizophrenia. By 'control', we mean the ability of the cognitive system to flexibly adapt its behaviour to the demands of particular tasks, favouring the processing of task-relevant information over other sources of competing information, and mediating task-relevant behaviour over habitual, or otherwise prepotent responses. There is a large body of evidence to suggest that the prefrontal cortex (PFC) plays a critical role in cognitive control. In previous work, we have used a computational framework to understand and develop explicit models of this function of PFC, and its impairment in schizophrenia. This work has lead to the hypothesis that PFC houses a mechanism for representing and maintaining context information. We have demonstrated that this mechanism can account for the behavioural inhibition and active memory functions commonly ascribed to PFC, and for human performance in simple attention, language and memory tasks that draw upon these functions for cognitive control. Furthermore, we have used our models to simulate detailed patterns of cognitive deficit observed in schizophrenia, an illness associated with marked disturbances in cognitive control, and well established deficits of PFC.Here, we review results of recent empirical studies that test predictions made by our models regarding schizophrenic performance in tasks designed specifically to probe the processing of context. These results showed selective schizophrenic deficits in tasks conditions that placed the greatest demands on memory and inhibition, both of which we have argued rely on the processing of context. Furthermore, we observed predicted patterns of deterioration in first episode vs multi-episode patients. We also discuss recent developments in our computational work, that have led to refinements of the models that allow us to simulate more detailed aspects of task performance, such as reaction time data and manipulations of task parameters such as interstimulus delay. These refined models make several provocative new predictions, including conditions in which schizophrenics and control subjects are expected to show similar reaction time performance, and we provide preliminary data in support of these predictions. These successes notwithstanding, our theory of PFC function and its impairment in schizophrenia is still in an early stage of development. We conclude by presenting some of the challenges to the theory in its current form, and new directions that we have begun to take to meet these challenges. In particular, we focus on refinements concerning the mechanisms underlying active maintenance of representations within PFC, and the characteristics of these representations that allow them to support the flexibility of cognitive control exhibited by normal human behaviour.Taken in tote, we believe that this work illustrates the value of a computational approach for understanding the mechanisms responsible for cognitive control, at both the neural and psychological levels, and the specific manner in which they break down in schizophrenia.