Neural Correlates of Perceptual Decision Making before, during, and after Decision Commitment in Monkey Frontal Eye Field
Neural Correlates of Perceptual Decision Making before, during, and after Decision Commitment in Monkey Frontal Eye Field
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DOI：
10.1093/cercor/bhr178
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发表时间：
2012-05-01
期刊：
影响因子：
3.7
通讯作者：
Gold, Joshua I.
中科院分区：
文献类型：
--
作者：
Ding, Long;Gold, Joshua I.
知觉决策需要一系列复杂的计算来实现、评估以及调整将感觉输入转化为类别判断的过程。对于特定的基础计算如何在不同脑区之间以及脑区内部分布，我们知之甚少。通过一个反应时（RT）运动方向辨别任务，我们发现与决策相关的信号的一种独特组合在猴子的额叶眼动区（FEF）中呈现。一些反应受到选择、运动强度和反应时的调节，这与感觉证据的时间累积相符。这些反应在行为反应之前汇聚到一个阈值水平，反映了决策的确定。其他反应即使在决策确定之后仍继续受到运动强度的调节，可能提供了一种记忆痕迹，以帮助根据奖励结果评估和调整决策过程。这两种反应类型均由具有窄峰和宽峰波形的额叶眼动区神经元编码，推测分别对应抑制性中间神经元和兴奋性锥体神经元，并且具有不同的视觉、视觉运动和运动特性，尽管频率不同。因此，整个额叶眼动区的神经元似乎对决策有多种贡献，且这些贡献仅与其他脑区的贡献部分重叠。这些结果有助于确定脑区网络如何相互作用以产生知觉决策。
Perceptual decision making requires a complex set of computations to implement, evaluate, and adjust the conversion of sensory input into a categorical judgment. Little is known about how the specific underlying computations are distributed across and within different brain regions. Using a reaction-time (RT) motion direction-discrimination task, we show that a unique combination of decision-related signals is represented in monkey frontal eye field (FEF). Some responses were modulated by choice, motion strength, and RT, consistent with a temporal accumulation of sensory evidence. These responses converged to a threshold level prior to behavioral responses, reflecting decision commitment. Other responses continued to be modulated by motion strength even after decision commitment, possibly providing a memory trace to help evaluate and adjust the decision process with respect to rewarding outcomes. Both response types were encoded by FEF neurons with both narrow- and broad-spike waveforms, presumably corresponding to inhibitory interneurons and excitatory pyramidal neurons, respectively, and with diverse visual, visuomotor, and motor properties, albeit with different frequencies. Thus, neurons throughout FEF appear to make multiple contributions to decision making that only partially overlap with contributions from other brain regions. These results help to constrain how networks of brain regions interact to generate perceptual decisions.