Inhibitory control by an integral feedback signal in prefrontal cortex: A model of discrimination between sequential stimuli
Inhibitory control by an integral feedback signal in prefrontal cortex: A model of discrimination between sequential stimuli
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DOI：
10.1073/pnas.0508072103
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发表时间：
2006-01-03
影响因子：
11.1
通讯作者：
Wang, XJ
中科院分区：
文献类型：
--
作者：
Miller, P;Wang, XJ
前额叶皮层（PFC）已知对行为的抑制控制至关重要，但其潜在机制尚不清楚。在此，我们提出抑制控制可由源自工作记忆的积分信号来实现，工作记忆是PFC的另一关键功能。具体而言，我们假设一个积分器将兴奋性输入转换为分级的记忆活动，该活动向上游传入神经元提供一个抑制信号（积分反馈控制）。我们在一个用于时间辨别任务的神经网络模型中展示了这一场景。该任务需要对初始刺激（刺激1）的振动频率（f1）进行工作记忆，随后将第二个刺激（刺激2）的频率（Q）与存储的f1进行比较并做出二元决策（f2 > f1或f2 < f1）。刺激1产生的积分反馈信号根据幅度差（f2 - f1）对后续输入进行门控。当一部分神经元对差异f2 - f1变得敏感时，反馈控制信号使它们在刺激1和刺激2之间对f1的调谐发生反转。这些神经元在延迟期间的放电率比刺激1期间的峰值放电率低。在延迟期间对f1敏感的第二组神经元，在刺激2期间达到的放电率取决于f1和f2中的最大值。我们的工作提出了一种跨时间辨别的电路机制，并预测了可通过实验进行测试的神经元行为。
The prefrontal cortex (PFC) is known to be critical for inhibitory control of behavior, but the underlying mechanisms are unclear. Here, we propose that inhibitory control can be instantiated by an integral signal derived from working memory, another key function of the PFC. Specifically, we assume that an integrator converts excitatory input into a graded mnemonic activity that provides an inhibitory signal (integral feedback control) to upstream afferent neurons. We demonstrate this scenario in a neuronal-network model for a temporal discrimination task. The task requires the working memory of the vibrational frequency (f1) of an initial stimulus (stimulus 1), followed by comparison of the frequency (Q) of a second stimulus (stimulus 2) with the stored f1 and a binary decision(f2 >f1 or f2 < f1). The integral feedback signal generated by stimulus 1 gates the later inputs based on the amplitude difference (f2 - f1). The feedback control signal enables a subset of neurons to reverse their tuning to f1l between stimulus 1 and stimulus 2, when they become tuned to the difference f2 - f1 These neurons maintain a lower firing rate during;he delay compared with their peak rate during stimulus 1. A second subset of neurons, tuned to f1 during the delay, reaches a rate during stimulus 2 that depends on the maximum of f1 and f2. our work suggests a circuit mechanism for discrimination across time and predicts neuronal behavior that can be tested experimentally.