Speed-accuracy tradeoff by a control signal with balanced excitation and inhibition.
Speed-accuracy tradeoff by a control signal with balanced excitation and inhibition.
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DOI：
10.1152/jn.00845.2013
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发表时间：
2015-07
影响因子：
2.5
通讯作者：
C. Lo;Cheng-Te Wang;Xiao-Jing Wang
中科院分区：
文献类型：
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作者：
C. Lo;Cheng-Te Wang;Xiao-Jing Wang
灵活行为的一个标志是大脑在决策过程中能够动态调整速度和准确性。近期研究表明，这种调整不仅改变决策阈值，还会调节证据积累的速率。然而，速率变化背后的神经元层面机制仍不清楚。在这项工作中，我们利用一个感知决策的脉冲神经网络模型证明，通过操纵一种具有平衡的兴奋和抑制（平衡突触输入，BSI）的自上而下的控制信号，可以有效地调整决策过程的速度和准确性。我们的模型预测，强调准确性高于速度会导致决策神经元的斜坡活动速率降低以及基线活动减少，这在近期对执行速度 - 准确性权衡任务的猴子进行的单神经元记录层面已经被观察到。此外，我们发现BSI抑制成分的增加会使决策时间分布发生偏移，并产生一个明显的指数尾，这在人类研究中是常见的。我们的研究结果表明，BSI可以作为一种自上而下的控制机制，在速度和准确性之间快速且参数化地进行权衡，并且当受试者在感知决策中强调准确性或速度时，这种认知控制信号都会出现。
A hallmark of flexible behavior is the brain's ability to dynamically adjust speed and accuracy in decision-making. Recent studies suggested that such adjustments modulate not only the decision threshold, but also the rate of evidence accumulation. However, the underlying neuronal-level mechanism of the rate change remains unclear. In this work, using a spiking neural network model of perceptual decision, we demonstrate that speed and accuracy of a decision process can be effectively adjusted by manipulating a top-down control signal with balanced excitation and inhibition [balanced synaptic input (BSI)]. Our model predicts that emphasizing accuracy over speed leads to reduced rate of ramping activity and reduced baseline activity of decision neurons, which have been observed recently at the level of single neurons recorded from behaving monkeys in speed-accuracy tradeoff tasks. Moreover, we found that an increased inhibitory component of BSI skews the decision time distribution and produces a pronounced exponential tail, which is commonly observed in human studies. Our findings suggest that BSI can serve as a top-down control mechanism to rapidly and parametrically trade between speed and accuracy, and such a cognitive control signal presents both when the subjects emphasize accuracy or speed in perceptual decisions.