The present study aimed to separate the neural activities between response inhibition and memory updating processes in the Count/Nocount task. Memory load was manipulated to investigate the memory updating process. Within each trial, participants were asked to count/withhold counting the number of O/X letters in the Count/Nocount task. The participants were asked to silently add 1 if a Count letter was presented in the low load condition, and add 2 in the high load condition. Data from 28 healthy participants showed that: (1) in both high load and low load conditions, the latencies of P2 and N2 components were shorter for the Nocount than Count trials, indicating faster attentional orienting and conflict monitoring processes for the Nocount stimuli (i.e., inhibition processes triggered by the Nocount stimuli against those response execution processes triggered by Count stimuli); (2) more positive frontal P3 amplitudes were evoked for the Nocount relative to the Count stimuli, indicating a more intensive response inhibition process for the Nocount trials; (3) a more positive parietal P3 component was evoked for the low load relative to high load condition, indicating a more intensive working memory updating process for the high load condition. This load effect was absent for the frontal P3 component, suggesting that the frontal P3 might not be associated with the memory updating process. In sum, both the cognitive inhibition process (reflected by the frontal P3 component) and working memory updating process (reflected by the parietal P3 component) appear to be involved in the Count/Nocount task.

本研究旨在分离计数/无计数任务中反应抑制和记忆更新过程之间的神经活动。操纵内存负载来调查内存更新过程。在每次试验中，参与者被要求计算/不计算 Count/Nocount 任务中 O/X 字母的数量。如果在低负载条件下出现 Count 字母，参与者被要求默默加 1，在高负载条件下加 2。来自 28 名健康参与者的数据显示：（1）在高负荷和低负荷条件下，Nocount 试验的 P2 和 N2 成分的延迟比 Count 试验短，表明 Nocount 刺激的注意力定向和冲突监测过程更快（即, 由 Nocount 刺激触发的抑制过程对那些由 Count 刺激触发的响应执行过程）；(2) 相对于 Count 刺激，Nocount 诱发了更正的额叶 P3 振幅，表明 Nocount 试验的反应抑制过程更强烈；(3) 相对于高负载条件，低负载诱发了更积极的顶叶 P3 分量，表明高负载条件下工作记忆更新过程更密集。额叶 P3 组件不存在这种负载效应，这表明额叶 P3 可能与记忆更新过程无关。总之，认知抑制过程（由额叶 P3 分量反映）和工作记忆更新过程（由顶叶 P3 分量反映）似乎都参与了 Count/Nocount 任务。