ISSN 0439-755X
CN 11-1911/B
主办:中国心理学会
   中国科学院心理研究所
出版:科学出版社

心理学报, 2019, 51(1): 48-57 doi: 10.3724/SP.J.1041.2019.00048

研究报告

奖赏通过增强信号监测提升认知控制

王宴庆1, 陈安涛1,*, 胡学平2, 尹首航1

1 西南大学心理学部, 认知与人格教育部重点实验室, 重庆 400715

2 江苏师范大学语言科学与艺术学院, 江苏省语言与认知神经科学重点实验室, 语言能力协同创新中心, 徐州 221009

Reward improves cognitive control by enhancing signal monitoring

WANG Yanqing1, CHEN Antao1,*, HU Xueping2, YIN Shouhang1

1 Key Laboratory of Cognition and Personality of Ministry of Education, Faculty of Psychology, Southwest University, Chongqing 400715, China

2 School of Linguistics and Arts, and Collaborative Innovation Center for Language Competence, Jiangsu Normal University, Xuzhou 221009, China

通讯作者: 陈安涛, E-mail: xscat@swu.edu.cn

收稿日期: 2018-03-5   网络出版日期: 2019-01-25

基金资助: * 国家自然科学基金项目.  61431013
* 国家自然科学基金项目.  31771254
中央高校基本科研业务费.  SWU1609106
中央高校基本科研业务费项目资助.  SWU1709107

Received: 2018-03-5   Online: 2019-01-25

摘要

认知控制是动态的、过程性的认知调控, 涉及监测和控制两个过程。先前研究表明奖赏可以提升认知控制, 但是奖赏是通过增强信号监测来提升认知控制的, 还是作用于控制过程来提升认知控制的, 是一个有待研究的重要问题。在本研究中, 我们设计了三个实验来调查这一问题。实验1采用Stop-Signal任务验证奖赏是否能提升认知控制; 实验2通过改变反应规则将Stop-Signal任务信号监测加工分离出来, 探讨实验1中奖赏的提升作用是否来源于奖赏对信号监测的增强; 实验3通过操纵注意资源损耗分析, 考察注意资源分配对信号监测的促进作用。实验1结果显示, 个体能更快地根据奖赏信息做出抑制反应。实验2结果表明, 在信号监测任务中, 个体能更加快速地监测到与当前抑制状态相冲突且和奖赏相关的反应信号, 据此可认为奖赏通过增强对相关信号的监测, 有助于个体更早地启动奖赏刺激信号所对应的反应, 更高效地控制冲突。实验3结果说明, 当任务难度增大, 注意资源损耗, 奖赏相关信号的反应时和正确率仍优于无奖赏信号, 说明注意资源的分配可以调节相关信号的监测速度。总体来看, 本研究通过一系列实验表明, 以目标为导向的行为发生过程中, 奖赏能有效提升认知控制效率, 其关键机制在于通过注意资源分配增强相关信号的监测。

关键词: 奖赏 ; 认知控制 ; 信号监测 ; Stop-Signal任务

Abstract

Cognitive control refers to two critical processes: signal monitoring and inhibitory control. Before executing inhibitory control, the individual first monitors the signal of conflict or warning. However, whether the reward influences signal monitoring or inhibitory control remains poorly understood. In addition, some literature employed pretask reward cueing to study the effect of reward, but the role of pretask reward cueing on cognitive control was influenced by response strategies rather than stimulus processing.
To address the above issues, the present study designed three novel variants of the classical stop signal task that combined the reward with certain stimuli or stimulus features and held stimulus-processing demands constant while varying attention demands. For experiment 1, participants tried to cancel responses on trials that were interrupted by the infrequent triangle but not to slow the initiation of the response. The results indicated that the SSRTs could be further accelerated if successful response inhibition were rewarded. Experiment 2 involved separation of signal monitoring from the stop signal task. Participants responded by pressing the left or right button when the trials were interrupted by the infrequent triangle. The results showed that participants could monitor a signal faster when the signal was associated with reward and conflicted with current behavior tendencies. Accordingly, we considered that the individual could more quickly activate behavior in correspondence with the signal and control the conflict because the signal monitoring was enhanced by reward, which indicated that the process needs more attention. Experiment 3 is the same as the second experiment, except that when trials were interrupted by an inverse triangle, participants made a dual button press. We found that the reaction time of the reward-related signal was shorter than that of the reward-unrelated signal in Go trials, even though the processing of the stop signal depletes the attention resource. These findings indicate that the reward-related signal captures more attention and enhances signal monitoring.
In summary, these findings show that the reward-related signal captures more attention than bias for the enhancement of signal monitoring, thereby leading to more efficient stimulus processing and improving cognitive control.

Keywords: reward ; cognitive control ; signal monitoring ; stop signal task

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本文引用格式

王宴庆, 陈安涛, 胡学平, 尹首航. 奖赏通过增强信号监测提升认知控制. 心理学报[J], 2019, 51(1): 48-57 doi:10.3724/SP.J.1041.2019.00048

WANG Yanqing, CHEN Antao, HU Xueping, YIN Shouhang. Reward improves cognitive control by enhancing signal monitoring. Acta Psychologica Sinica[J], 2019, 51(1): 48-57 doi:10.3724/SP.J.1041.2019.00048

1 引言

认知控制是指在以目标为导向的行为发生过程中, 个体对与任务无关的信息及冲动性行为倾向的抑制能力, 它是完成认知活动所必需的高级认知功能(Aron, Robbins, & Poldrack, 2014; Braver et al., 2014; Hampshire & Sharp, 2015)。认知控制加工是一种动态的、过程性的认知调控, 通常涉及监测和控制两个过程(Carter et al., 2000; Kerns, Cohen, MacDonald Ⅲ, Cho, Stenger, & Carter, 2004; Botvinick, Nystrom, Fissell, Carter, & Cohen, 1999; Botvinick, Cohen, & Carter, 2004), 个体在早期知觉加工阶段监测到(冲突或警告)信号的出现, 然后实施抑制控制。成功的抑制控制需要个体快速有效的监测到信号的出现, 然后进一步做出正确的反应选择。

大量研究表明奖赏(reward)作为一种外部刺激诱因, 能够通过诱发特定的情绪和动机提升认知控制(Botvinick & Braver, 2015; Braver et al., 2014; Pessoa, 2009), 即相比于无奖赏刺激, 个体能有效地抑制分心刺激带来的干扰, 提高奖赏相关刺激的反应(Boehler, Hopf, Stoppel, & Krebs, 2012; Boehler, Schevernels, Hopf, Stoppel, & Krebs, 2014; Krebs, Boehler, Egner, & Woldorff, 2011)。例如, Krebs等 (2011)采用Stroop任务发现, 当靶刺激与奖赏相关联时, 个体能更加快速且正确地排除干扰, 降低冲突并做出按键反应。但是目前尚未有研究探讨奖赏是否对信号监测产生影响, 而一般的认知控制研究发现个体对冲突的控制依赖于监测功能(Egner & Hirsch, 2005; Botvinick et al., 1999)。个体对信号的监测有别于反应控制, 从功能来讲, 信号监测主要负责在视觉范围内探测、搜索目标行为相关的信号, 然后将相关信息传递给反应控制, 而反应控制负责维持目标相关行为, 抑制目标无关行为; 从认知控制的执行过程来讲, 信号监测发生于注意加工的早期阶段, 先于反应控制。先前研究表明目标行为发生过程中, 个体对冲突信号的有效监测会优化后续的反应输出(唐丹丹, 陈安涛, 2013; 蒋军, 向玲, 张庆林, 陈安涛, 2014)。那么奖赏是否是通过增强信号监测提升认知控制, 在这种机制下, 奖赏相关刺激捕获更多的注意, 个体能更快地监测到奖赏相关信号的出现, 更早地启动、实施抑制反应; 亦或者直接作用于认知控制功能, 即奖赏增强了刺激-反应映射, 个体面对奖赏相关的刺激时能更快地提取与之对应的反应规则。先前研究用来考察认知控制的相关任务(如:Go/NoGo、Flanker、Stroop等)的测试结果既反映了信号监测能力, 同时也反映冲突控制能力, 因此以往的研究在探讨奖赏提升认知控制时, 无法提供直接的证据说明提升效应是否来自于奖赏对信号监测的增强(Chikazoe et al., 2009; Sharp et al., 2010; van Steenbergen, Band, & Hommel, 2012)。

在认知研究领域, Stop-Signal任务是研究认知控制的常用范式, 在该范式中停止信号是小概率事件, 出现的潜伏期是根据被试的反应进行动态调整, 当停止信号突然出现时, 要求个体在反应过程中合理分配注意, 快速监测信号的出现, 然后将已经处于准备状态的反应停止下来(Lee et al., 2016; Sharp et al., 2010; Xu et al., 2017)。个体更快地监测到停止信号的出现, 则能更早地启动停止反应, 抑制按键冲动。由于Stop-Signal任务加工过程相对简单, 仅包括对停止信号的监测和抑制, 并且能根据实验设计与个体的表现计算出个体对停止信号抑制的反应时间, 有效地评估个体的认知控制能力。本研究将采用Stop-Signal任务测量奖赏对停止信号加工的促进作用, 以此考察奖赏提升认知控制的机制。

此外, 奖赏的呈现方式对认知控制有不同的影响。先前研究在操作奖赏信息时, 是在每个试次(组块)之前呈现奖赏线索, 在这种操作下, 奖赏主要通过诱发被试保持一种持续的准备状态, 积极维持目标信息, 进一步调节个体解决冲突、抑制反应的能力(Botvinick & Braver, 2015; van den Berg, Krebs, Lorist, & Woldorff, 2014)。由于这种方法需要被试在反应前持续维持奖赏相关线索信息, 占用的认知资源比较多, 认知负荷大, 会对实验任务本身的操作产生一定的影响, 不能够准确地考察奖赏对刺激信号加工本身的影响机制。

为此, 本研究在Stop-Signal任务基础上采用刺激-奖赏联结的方法将一类或多类刺激与奖赏进行联结, 以此来论证奖赏提升认知控制的机制。不同于奖赏线索的影响机制, 刺激-奖赏联结通过影响个体对即时出现的目标相关信息的注意加工, 进一步优化行为输出(Boehler et al., 2014; Krebs et al., 2011)。此外, 本研究将采用三个实验来探讨奖赏通过增强信号监测提升认知控制这一机制。在实验1中, 我们通过Stop-Signal任务考察奖赏对认知控制的提升效应; 实验1的结果可以说明奖赏提升了认知控制, 但是不能反映提升效应来自于监测功能还是控制功能的增强。基于实验1的结果, 实验2在Stop-Signal任务的基础上改变反应规则, 要求被试对向左/向右箭头不做任何反应(Stop), 此时被试处于抑制激活状态, 然后给予一个小概率的反应信号(Go), 要求被试又快又准确的进行按键反应, 该加工过程与Stop-Signal任务中停止信号的加工过程相同, 即已经形成的反应倾向(Go/Stop)与小概率刺激信号代表的反应活动(Stop/Go)形成冲突。不同于传统的Stop-Signal任务, 实验2中, 个体监测到Go信号的出现, 立即启动按键反应, 能够通过反应时反映个体对信号的监测; 此外, 先前研究表明奖赏信息能够通过调节注意资源的分配增强个体对刺激信号的加工(Krebs et al., 2011; Krebs, Boehler, Appelbaum, & Woldorff, 2013; Krebs, Boehler, & Woldorff, 2010)。实验3在实验2的规则基础上加入停止信号, 由于加工停止信号会占用Go信号的注意加工资源。如果奖赏刺激可以吸引更多的注意资源来增强信号监测加工, 那么即使在注意资源损耗的情况下, 奖赏相关的信号仍可以吸引更多的注意资源, 行为表现优于无奖赏刺激。

2 方法

2.1 被试

共有26人(男生12人, 年龄在17岁~24岁之间, 平均年龄为20.5岁)参加实验, 所有被试均为自愿参加实验, 且身心健康、右利手、视力或矫正视力正常、非色盲或色弱。实验前均签署实验知情同意书, 实验完成后根据每名被试的任务表现给予相应的报酬。

2.2 实验仪器

实验采用计算机呈现刺激, 显示器为17寸戴尔E2014HC, 分辨率为1600×900, 刷新率为60 Hz。实验程序由E-prime编制运行, 被试在键盘上做按键反应, 反应时和正确率由计算机自动记录。被试双眼距屏幕的距离约为60 cm, 在一个亮度适中的单间实验室里单独参加测试。

2.3 任务和程序

本研究由三个实验组成, 每个实验呈现的刺激及流程见图1, 首先在屏幕中央呈现“+”500 ms, 接下来呈现向左或向右的白色箭头, 偶尔在箭头上面会出现向上或向下且不同颜色(蓝色或黄色)的三角形, 要求被试根据每部分相应的反应规则进行按键反应, 最后空屏500~1000 ms后开始下一试次。

图1

图1   实验流程图

A, 实验1中, 判断箭头朝向, 箭头上出现向上或向下的三角形(停止信号)时停止反应; B, 实验2中, 不对箭头反应, 箭头上出现向上或向下的三角形(Go信号)时判断箭头朝向; C, 实验3中, 不对箭头反应, 箭头上出现向下的三角形(停止信号)时不做反应, 箭头上出现向上的三角形(Go信号)时判断箭头朝向。


实验1为Stop-Signal任务, 主要探讨被试的抑制能力水平。屏幕出现向左或向右的箭头时, 要求被试又快又准确的判断箭头朝向, 箭头朝左按“F”键, 箭头朝右按“J”键, 当箭头上面出现向上或向下的三角形时, 要求被试停止按键, 不做任何按键反应。

实验2改变Stop-Signal任务的反应规则, 探讨被试对信号刺激的监测。任务要求被试屏幕出现向左或向右的箭头时不要做任何按键反应, 当箭头上面出现向上或向下的三角形时, 又快又准确的判断箭头的朝向, 箭头朝左按“F”键, 箭头朝右按“J”键。

实验3既包括对信号的抑制规则, 也包括对信号的反应规则。要求被试当屏幕出现向左、向右的箭头或箭头上面出现向下的三角形时, 不要做任何按键反应, 当箭头上面出现向上的三角形时, 又快又准确的判断箭头的朝向, 箭头朝左按“F”键, 箭头朝右按“J”键。

实验前会告知被试, 参加本次实验首先会得到30元人民币, 但最终获得的报酬取决于其在实验过程中的表现。实验中为了避免被试分心去计算金钱的数量, 影响实验操作, 本研究将所有的金钱数转换成游戏币进行操作(100游戏币 = 0.1元人民币) (Krawczyk, Gazzaley, & D'Esposito, 2007)。按照反应规则正确对黄色三角形(向上或向下)信号反应, 每次得到100游戏币, 做错扣除100游戏币; 按照反应规则正确对蓝色三角形(向上或向下)信号反应, 每次得到0游戏币, 做错扣除0游戏币。先前研究发现不同颜色的刺激会对认知控制产生影响(Wang, Zhao, Xue, & Chen, 2016), 因此在实验中不同颜色所对应的奖赏大小在被试间进行平衡。每个组块或每部分实验结束后被试可稍作休息, 以保证较好的状态。

实验1中停止信号与Go信号间的时距(即停止信号延迟, stop signal delay, SSD)按照追踪算法设置。初始SSD设置为200 ms, 然后根据被试的反应做动态调整:如果被试在当前停止试次中成功抑制住了反应, 下一个Stop试次的SSD延长34 ms, 以增大抑制的难度; 如果被试在当前停止试次中未能抑制住反应, 下一个Stop试次的SSD减少34 ms, 以增加抑制的可能性。这种追踪算法使SSD呈阶梯式的动态变化, 保证被试成功抑制50%的停止试次。如果被试未能抑制住反应, 则停止信号在被试按键后即消失, 如果被试抑制成功, 则停止信号的呈现时间为(1000 - SSD) ms。实验2和实验3中三角形信号与箭头间的时距(signal delay, SD)随机变化, 变化的范围根据以往的研究(Erika-Florence, Leech, & Hampshire, 2014; Hampshire & Sharp, 2015)设置为312 ± 115 ms。

实验1和实验2均有270个试次(每个实验有三个组块构成, ), 每个实验中三角形信号出现的次数为90次(奖赏信号45个, 占总试次的17%; 无奖赏信号45个, 占总试次的17%)。实验3有360个试次(有四个组块构成), 三角形信号出现的次数为120次(Go与Stop奖赏信号各30个, 各占总试次的8%; Go与Stop无奖赏信号各30个, 各占总试次的8%)。每个实验前均有30个练习试次, 练习试次中三角形出现的概率为50% (奖赏与无奖赏试次各占50%), 每次练习结束后要求被试口头报告是否已经掌握反应规则以及不同颜色所代表的奖赏数量, 若被试没有掌握反应规则或奖励规则, 则要求被试重新进行练习。此外, 为了避免三角形信号所对应的反应在不同实验规则中的混淆, 实验1、2、3的顺序是固定的。实验中所有试次均按伪随机顺序呈现, 三角形信号连续出现不超过两次。

3 结果

停止信号反应时(stop signal reaction time, SSRT)是Stop-Signal任务中测量抑制能力的关键指标, 本研究采用相对更为精确的积分法(integration method)估算SSRT。即假设n是Stop试次中错误反应的概率, t是Go试次中正确反应的数量, 将正确执行反应时(Go RT)从快到慢排序, 停止信号反应时(SSRT) = 第n×t个位置的执行反应时(Go RT) - 平均停止信号延迟(SSD) (Boehler et al., 2012; Verbruggen, Chambers, & Logan, 2013)。Go信号和停止信号相关统计指标见表1

表1   实验1 Stop-Signal任务行为指标数据(M ± SD)

行为指标无奖赏试次奖赏试次
停止信号SSD (ms)236 ± 85247 ± 88
停止信号SSRT (ms)233 ± 73220 ± 73
停止信号正确率0.51 ± 0.060.51 ± 0.07
Go试次反应时(ms)493 ± 77--
Go试次正确率0.98 ± 0.02--

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实验1中, 奖赏停止试次和无奖赏停止试次正确率均接近50%, 且两组之间差异不显著, t(25) = 0.70, p > 0.05, 说明本实验所采用的追踪算法是有效的。奖赏停止试次和无奖赏停止试次分别采用追踪算法计算SSD, 奖赏试次的SSD显著大于无奖赏试次的SSD (t(25) = 2.85, p < 0.01, Cohen’s d = 1.14), 奖赏试次的SSRT显著的小于无奖赏试次的SSRT (t(25) = 2.20, p < 0.05, Cohen’s d = 0.88), 说明奖赏信息加快了抑制反应, 缩短了停止信号的反应时。

分析实验2比较奖赏对信号监测的影响, 对三角形Go信号的反应时和正确率进行统计分析(见图2A), 个体对于奖赏信号的监测显著快于无奖赏信号, t(25) = 2.13, p < 0.05, Cohen’s d = 0.85; 两者之间的正确率差异不显著, t(25) = 0.43, p > 0.05。

图2

图2   实验结果图

A:实验2信号监测的反应时和正确率; B:实验2与实验3中Go试次的反应时和正确率


比较实验3与实验2 Go试次反映指标考察注意资源的分配。对Go试次反应时和正确率分别做2(实验序列:实验2、实验3)×2(奖赏信息:奖赏信号、无奖赏信号)重复测量方差(见图2B)。对反应时分析发现奖赏信息的主效应显著, F(1, 25) = 11.20, p < 0.01, η2 = 0.309, 奖赏试次的反应时(395 ± 7.49 ms)显著快于无奖赏试次的反应时(412 ± 7.51 ms); 实验序列的主效应显著, F(1, 25) = 63.50, p < 0.001, η² = 0.718, 实验3平均反应时(439 ± 7.36 ms)显著大于实验2平均反应时(368 ± 9.34 ms), 两者交互作用不显著, p > 0.05。此外, 基于正确率的分析发现奖赏信息的主效应显著, F(1, 25) = 11.75, p < 0.01, η² = 0.32, 奖赏试次的正确率(0.95 ± 0.01)显著大于无奖赏试次的正确率(0.87 ± 0.02); 实验序列的主效应显著, F(1, 25) = 8.87, p < 0.01, η² = 0.26, 实验3正确率(0.88 ± 0.02)显著小于实验2正确率(0.94 ± 0.01); 两者交互作用显著, F(1, 25) = 7.36, p < 0.05, η² = 0.23; 简单效应分析表明, 只有在实验3中奖赏试次和无奖赏试次正确率差异显著。进一步求出从实验2到实验3中Go试次正确率差异量并做比较发现, 无奖赏试次正确率差异量(0.13 ± 0.2)显著大于奖赏试次(0.03 ± 0.06), t(25) = 2.85, p < 0.01, Cohen’s d = 1.14。

个体的注意资源随着实验的进行会逐渐被损耗, 在任务加工过程中, 个体需要平衡速度和准确率。基于此, 对实验3分析表明(见图3A), 三角形所对应的Go信号试次中, 奖赏信号的反应时显著快于无奖赏信号反应时(t(25) = 2.79, p < 0.01, Cohen’s d = 1.12), 且奖赏刺激的正确率显著高于无奖赏刺激正确率(t(25) = 2.93, p <0.01, Cohen’s d = 1.72); 而在三角形所对应的停止信号试次中, 奖赏刺激的正确率显著低于无奖赏刺激正确率(t(25) = 3.12, p < 0.01, Cohen’s d = 1.25); 进一步将实验3分成早期组块(第1~2个组块)和晚期组块(第3~4个组块) (见图3B)。对停止信号的正确率做2(组块:早期组块、晚期组块)×2(奖赏信息:奖赏信号、无奖赏信号)重复测量方差分析, 奖赏的主效应显著, F(1, 25) = 9.95, p < 0.01, η² =0.285, 无奖赏刺激的正确率(0.97 ± 0.01)显著的高于奖赏刺激正确率(0.91 ± 0.02), 组块的主效应不显著(p > 0.05), 即停止信号的正确率在早期组块和晚期组块差异不显著, 组块和奖赏信息的交互作用不显著(p > 0.05); 对Go信号的反应时做2(组块:早期组块、晚期组块)×2(奖赏信息:奖赏信号、无奖赏信号)重复测量方差分析, 奖赏的主效应显著, F(1, 25) = 7.55, p < 0.05, η² = 0.205, 奖赏信号的反应时(430 ± 7.32 ms)显著比无奖赏信号反应时(448.40 ± 9.51 ms)短, 组块的主效应不显著, 奖赏信息与组块的交互作用显著, F(1, 25) = 5.37, p < 0.05, η² = 0.177, 在早期组块中, 奖赏信号的反应时(418 ± 9.90 ms)显著快于无奖赏信号(448 ± 11.38 ms), 而在晚期组块, 奖赏信号反应时(441 ± 8.41 ms)与无奖赏信号反应时(448 ± 9.32 ms)之间差异不显著; 对Go反应试次的正确率做2(组块:早期组块、晚期组块)×2(奖赏信息:奖赏信号、无奖赏信号)重复测量方差分析, 奖赏的主效应显著, F(1, 25) = 8.49, p < 0.01, η² = 0.232, 奖赏刺激的正确率(0.93 ± 0.01)显著的高于无奖赏刺激正确率(0.85 ± 0.03), 但是组块的主效应、奖赏信息和组块的交互作用不显著(p > 0.05)。

图3

图3   实验结果图

A:实验3中Stop试次的正确率、Go试次的正确率和反应时; B:实验3早期组块和晚期组块Go试次的反应时、正确率和Stop试次的正确率。


4 讨论

本研究基于Stop-Signal任务考察了奖赏对认知控制的提升机制。在Stop-Signal任务中, 相比于无奖赏信号, 个体能更快地抑制奖赏相关的信号。这与前人研究结果一致(Boehler et al., 2012; Boehler et al., 2014; Schevernels et al., 2015), 即奖赏提高了认知控制相关任务的行为表现, 表明奖赏可以提升个体的认知控制能力。不同于以往通过“奖赏线索”诱发被试积极的准备状态提升认知控制的研究, 本研究中采用刺激-奖赏联结的呈现方式, 因此奖赏的提升效应主要来源于奖赏对刺激信号本身加工的影响。

认知控制加工是一种过程性的认知调控。fMRI的研究表明, 冲突信号激活了负责信号监测的前扣带回(anterior cingulate cortex, ACC), 随后ACC将信号传递给负责控制加工的背外侧前额叶(dorsolateral prefrontal cortex, dlPFC), 使我们的大脑能更好地完成任务(Boehler et al., 2014; Botvinick & Braver, 2015; Krebs et al., 2011; Westbrook & Braver, 2016)。本研究通过Stop-Signal任务侧重于认知控制加工所涉及具体的过程, 探讨奖赏对信号监测和反应控制的影响。实验1的结果表明奖赏相关的停止信号的SSRT更短, 表明个体能更快速地对奖赏相关的信号发起抑制反应。赛马模型(horse-race model) (Logan & Cowan, 1984)假设认为抑制反应的发生取决于停止信号诱发的停止反应和Go信号诱发的按键反应两个独立的加工过程相互竞争的结果, 如果停止反应在Go反应之前完成, 则实现对行为的抑制; 相反, 如果Go反应在停止反应之前完成, 则抑制失败。进一步有研究者采用MEG发现, Go反应和停止反应间的的竞争结果依赖于个体早期知觉加工阶段对Go信号和停止信号的监测(Boehler et al., 2009)。个体快速监测到停止信号的出现, 则能更早地启动停止反应, 实施对按键行为的抑制。Salinas和Stanford (2013)近期采用心理物理法同样发现在停止信号任务中, 个体能否成功地实施抑制反应取决于早期知觉加工阶段对停止信号快速、有效的监测。这些研究结果均说明在早期知觉加工阶段个体对任务相关信号刺激的注意加工是提升抑制控制的关键因素之一(Boehler et al., 2009; Salinas & Stanford, 2013)。同时, 大量研究表明奖赏能够在早期注意加工增强相关刺激的知觉表征, 即个体能更快地监测到奖赏相关信号的出现(Anderson, Laurent, & Yantis, 2011; Barbaro, Peelen, & Hickey, 2017)。本研究实验2发现, 当个体处于已经激活的抑制状态, 突然出现一个与当前反应倾向冲突的无奖赏/奖赏信号要求其反应时, 奖赏相关信号反应时更短, 说明奖赏相关信号能更快地被监测到, 进一步做出按键反应。由此我们推论停止信号的加工过程中, 相比于无奖赏信号, 奖赏相关的停止信号能够更快地被个体监测到, 停止反应先于Go反应被启动并且完成, 反应成功被抑制。该推论得到EEG相关研究的支持, 研究发现在Stop signal任务中, 相比于抑制失败的试次, 抑制成功的试次N1波幅增大, N1成分与特定目标的视觉注意有关(Boehler et al., 2009; Schevernels et al., 2015), 而奖赏相关的停止信号在知觉加工阶段能诱发更大的N1波幅(Schevernels et al., 2015), 表明奖赏能在早期知觉加工阶段增强信号监测, 因此在Stop- Signal任务个体能更快地对奖赏相关的信号发起抑制反应。

此外, 与当前研究相似的是, 基于情绪面孔来考察情绪刺激对Stop-Signal任务影响的研究发现相比中性面孔, 被试能更快地对消极情绪面孔(愤怒、悲伤等)做出抑制反应, 即消极面孔的SSRT更短, 作者认为该现象是由于消极面孔在知觉加工阶段增强了其知觉表征, 促进了相关信号的监测(Derntl & Habel, 2016; Pawliczek et al., 2013; Pessoa, 2009; Pessoa & Engelmann, 2010)。而来自知觉加工的研究表明, 奖赏刺激和消极情绪面孔在视觉搜索、空间定向等范式中的任务表现都优于中性/无奖赏刺激, 即奖赏刺激和消极情绪面孔在早期知觉阶段加工均会得到增强, 个体能更快地监测到此类刺激的出现(Hickey & Peelen, 2015; Navalpakkam & Treisman, 2010)。结合本研究结果, 我们认为奖赏信号的SSRT比无奖赏信号的更短是由于个体更快地监测到奖赏相关信号的出现, 进一步提升对行为的抑制能力。

需要指出的是, 尽管本研究中采用奖赏-刺激联结的方式考察奖赏通过对信号本身加工的影响提高任务相关表现, 但是不能完全排除奖赏动机对认知控制的提升作用。Pessoa (2009)提出奖赏动机能够调节注意资源分配, 进而产生加工特异性效应。在实验2和实验3中, 奖赏Go试次的反应时均优于无奖赏试次, 并且在规则简单的实验2中奖赏试次与无奖赏试次正确率无差异; 而在实验规则复杂的实验3中, 奖赏正确率显著大于无奖赏试次, 表明即使在其它加工过程中占用了部分注意资源, 奖赏属性的刺激仍会吸引更多的注意资源以保证正确率。在实验3早、晚期, 任务加工过程中会损耗注意资源, 无奖赏Go试次的反应时和正确率在这一过程中没有明显的变化, 说明个体会用有限的注意资源加工无奖赏信号, 对无奖赏信号的加工已经处于最低执行水平, 注意资源的损耗对其不会有影响; 而奖赏相关信号占用更多的注意资源, 随着注意资源的损耗, 个体为了获得更多的奖赏, 就要权衡速度和准确性, 因此在晚期组块会放慢对奖赏信号Go的反应, 保证Go试次和停止试次的正确率。总之, 实验过程中明确告知被试对其中一种颜色的目标做出反应会得到奖赏, 被试就有意识地将颜色和不同水平的奖赏联结起来, 对奖赏相关颜色的信号反应动机可能会更强, 与此同时奖赏动机则会分配更多注意资源加工奖赏相关刺激。此外, 研究表明奖赏动机会促进多巴胺的释放(Arias-carrión & Pŏppel, 2007; Westbrook & Braver, 2016), 同时, 多巴胺使与奖赏联结的刺激在神经系统中的知觉表征增强(Krebs et al., 2012; Westbrook & Braver, 2016)。据此, 我们认为在奖赏-刺激联结的呈现方式下, 奖赏动机可能会通过注意资源增强相关信号的监测来进一步提升认知控制。

奖赏动机对行为的发生有非常重要的影响, 值得注意的是奖赏不仅可以提升目标行为表现, 同时也会损害目标行为表现。先前有研究采用停止信号任务发现当奖赏可得性与Go信号相关联时, 即告知被试在奖赏组块中只有正确且快速的对左右箭头朝向做出判断才可以获得奖赏, 相比于无奖赏的组块, 被试对箭头朝向的判断更快, 但是停止信号相关的SSRT更长, 说明奖赏损害了反应控制。这是由于当奖赏与Go信号相关联时, 个体会分配更多注意资源加工Go试次以确保收益最大化; 同时在Go反应与停止反应相关竞争的过程中, 奖赏加快了个体对Go反应的启动, 抑制反应的失败率上升, SSRT变长(Leotti & Wager, 2010)。在本研究一中奖赏的可得性主要与停止信号的反应相关, 结果发现奖赏能够提升反应抑制。这表明当奖赏驱动行为的方向与目标行为方向一致时, 奖赏会强化目标性行为的表征与发生, 提升目标行为的任务表现; 相反, 当奖赏驱动行为的方向与目标性行为方向不一致时, 奖赏会损害目标行为的发生。这一观点在注意研究领域得到大量的证明, 例如:研究发现当奖赏与目标刺激相关联时, 个体能更快地将注意集中在目标刺激, 进而正确快速地进行按键反应; 相反, 当奖赏与分心刺激相关联时, 奖赏造成的对分心刺激的过度注意集中会妨碍个体对目标刺激的识别与反应, 导致个体的正确率下降、反应时增加(Anderson et al., 2011; Barbaro et al., 2017; Hickey et al, 2015; Krebs et al., 2011; Krebs et al., 2013)。研究者们认为这是由于奖赏增强了相关刺激信号的早期知觉表征, 进而影响了个体的反应输出(Krebs et al., 2011)。有趣的是在本研究的实验3中, 当奖赏既与Go信号又与停止信号相关联时, 结果发现奖赏相关的停止信号的正确率显著低于无奖赏相关的停止信号, 而奖赏相关的Go信号的反应优于无奖赏相关的Go信号的反应。这是由于在人类的进化与发展过程中, 奖赏通常与趋近性行为相联系, 被试看见奖赏信号会冲动性的做出趋近反应(Freeman & Aron, 2016; Freeman, Razhas, & Aron, 2014), 这与按键反应的发生方向是一致的, 因此奖赏相关Go信号反应时更短, 正确率更高; 但是, 在抑制规则和反应规则相互转换过程中, 被试在经历了Go反应规则后, 再对停止信号进行抑制, 需要更强的反应控制能力, 尤其是在加工奖赏相关的停止信号时, 被试需要调节动机与反应之间的冲突, 因此抑制奖赏相关的停止信号更难, 相比于无奖赏停止信号, 奖赏停止信号的正确率更低。这与Freeman和Aron (2016)采用Go/No-Go任务的研究结果一致, 即当奖赏信息既与Go信号又与No-Go信号相关联时, 奖赏会加快Go反应的反应速度, 但是会降低No-Go反应的正确率。

综合而言, 本研究通过三个实验研究表明, 在以目标为导向的行为发生过程中, 奖赏系统能推动目标指向行为, 奖赏相关的信号会吸引更多的注意资源, 增强信号监测, 进一步提升认知控制。此外, 本研究对奖赏提升认知控制机制的论证, 也为未来深入开展奖赏与认知控制的研究提供了新的视角和启示, 即不仅要探讨奖赏动机及其强度在奖赏对认知控制影响中的加工机制; 也要关注在信号监测和冲突控制与奖赏的交互作用上的群体差异; 基于本研究中奖赏能提升个体对停止信号抑制反应速度的发现, 后续研究可针对监测功能和控制功能分别提出训练和干预方案, 实现认知控制能力的有效提升。

5 结论

本研究结果显示, 个体在Stop-Signal任务中能够依据奖赏信息更快地抑制停止信号, 这表明奖赏可以提升认知控制; 为了考察奖赏对信号监测的影响, 我们进一步改变反应规则, 要求个体监测到信号之后立即按键反应, 结果发现奖赏相关的信号反应时更短, 表明个体能更快地监测到奖赏相关信号; 除此, 通过增加实验规则难度, 损耗注意资源表明, 奖赏相关的信号会吸引更多的注意资源, 进而优化行为的发生与输出。由于在认知控制的加工过程中, 个体先监测到信号, 然后进行控制, 并且我们用来考察信号监测的任务与Stop-Signal任务加工过程相同, 都是对小概率且与当前激活状态冲突的信号进行反应, 基于此, 我们的结果说明奖赏可以通过调节注意资源分配, 增强个体对相关刺激的监测, 进一步提升认知控制。

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Value-driven attentional capture

Proceedings of the National Academy of Sciences of the United States of America, 108( 25), 10367-10371.

DOI:10.1073/pnas.1104047108      URL     [本文引用: 2]

Barbaro L., Peelen M. V., & Hickey C . ( 2017).

Valence, not utility, underlies reward-driven prioritization in human vision

Journal of Neuroscience, 37( 43), 1128-1117.

DOI:10.1523/JNEUROSCI.1128-17.2017      URL     [本文引用: 2]

Objects associated with reward draw attention and evoke enhanced activity in visual cortex. What is the underlying mechanism? One possibility is that reward9s impact on vision is mediated by unique circuitry that modulates sensory processing, selectively increasing the salience of reward-associated stimuli. Alternatively, effects of reward may be part of a more general mechanism that prioritizes the processing of any beneficial object, importantly including stimuli that are associated with the evasion of loss. Here, we test these competing hypotheses by having male and female humans detect naturalistic objects associated with monetary reward, the evasion of equivalent loss, or neither of these. If vision is economically normative, processing of objects associated with reward and evasion of loss should be prioritized relative to neutral stimuli. Results from fMRI and behavioral experiments show that this is not the case: whereas objects associated with reward were better detected and represented in ventral visual cortex, detection and representation of stimuli associated with the evasion of loss were degraded. Representations in parietal cortex reveal a notable exception to this pattern, showing enhanced encoding of both reward- and loss-associated stimuli. Experience-driven visual prioritization can thus be economically irrational, driven by valence rather than objective utility.SIGNIFICANCE STATEMENT Normative economic models propose that gain should have the same value as evasion of equivalent loss. Is human vision rational in this way? Objects associated with reward draw attention and are well represented in visual cortex. This is thought to have evolutionary origins, highlighting objects likely to provide benefit in the future. But benefit can be conferred not only through gain, but also through evasion of loss. Here we demonstrate that the visual system prioritizes real-world objects presented in images of natural scenes only when these objects have been associated with reward, not when they have provided the opportunity to evade financial loss. Visual selection is thus non-normative and economically irrational, driven by valence rather than objective utility.

Boehler C. N., Appelbaum L. G., Krebs R. M., Hopf J-M., & Woldorff M. G . ( 2012).

The influence of different Stop- signal response time estimation procedures on behavior-behavior and brain-behavior correlations

Behavioural Brain Research, 229( 1), 123-130.

DOI:10.1016/j.bbr.2012.01.003      URL     PMID:3306010      [本文引用: 2]

The fundamental cognitive-control function of inhibitory control over motor behavior has been extensively investigated using the Stop-signal task. The critical behavioral parameter describing stopping efficacy is the Stop-signal response time (SSRT), and correlations with estimates of this parameter are commonly used to establish that other variables (e.g., other behavioral measures or brain activity measures) are closely related to inhibitory motor control. Recently, however, it has been argued that SSRT estimates can be strongly distorted if participants strategically slow down their responses over the course of the experiment, resulting in the SSRT no longer reliably representing response-inhibition efficacy. Here, we performed new analyses on behavioral and functional data from an fMRI version of the Stop-signal task to gauge the consequences of using different SSRT estimation approaches that are differentially prone to the influence of strategic response slowing. The results indicate that the SSRT estimation approach can dramatically change behavior ehavior correlations. Specifically, a correlation between the SSRT and Go-trial accuracy that was highly significant with one estimation approach, virtually disappeared for the other. Additional analyses indeed supported that this effect was related to strategic response slowing. Concerning brain ehavior correlations, only the left anterior insula was found to be significantly correlated with the SSRT within the set of areas tested here. Interestingly, this brain ehavior correlation differed little for the different SSRT-estimation procedures. In sum, the current results highlight that different SSRT-estimation procedures can strongly influence the distribution of SSRT values across subjects, which in turn can ramify into correlational analyses with other parameters.

Boehler C. N., Hopf J.-M., Stoppel C. M., & Krebs R. M . ( 2012).

Motivating inhibition - reward prospect speeds up response cancellation

Cognition, 125( 3), 498-503.

DOI:10.1016/j.cognition.2012.07.018      URL     PMID:22921189      [本文引用: 1]

Reward prospect has been demonstrated to facilitate various cognitive and behavioral operations, particularly by enhancing the speed and vigor of processes linked to approaching reward. Studies in this domain typically employed task regimes in which participants overt responses are facilitated by prospective rewards. In contrast, we demonstrate here that even the cancellation of a motor response can be accelerated by reward prospect, thus signifying reward-related benefits on restraint rather than approach behavior. Importantly, this facilitation occurred independent of strategy-related adjustments of response speed, which are known to systematically distort the estimation of response-cancellation speed. The fact that motivational factors can indeed facilitate response inhibition is not only relevant for understanding how motivation and response inhibition interact in healthy participants but also for work on various patient groups that display response-inhibition deficits, suggesting that core differences in the ability to inhibit motor responses have to be differentiated from motivational factors.

Boehler C. N., Müente T. F., Krebs R. M., Heinze H.-J., Schoenfeld M. A., & Hopf J. M . ( 2009).

Sensory MEG responses predict successful and failed inhibition in a stop-signal task

Cerebral Cortex, 19( 1), 134-145.

DOI:10.1093/cercor/bhn063      URL     PMID:18440947      [本文引用: 3]

Abstract In the present study magnetoencephalographic recordings were performed to investigate the neural mechanisms underlying the stopping of manual responses. Subjects performed in a Stop-signal task in which Go-stimuli (S1), requiring a rapid motor response, were sometimes rapidly followed by a Stop-stimulus (S2) indicating to withhold the already initiated response to S1. Success of stopping strongly depended on the early perceptual processing of S1 and S2 reflected by the magnetic N1 component. Enhanced processing of S1 facilitated the execution of the movement, whereas enhanced processing of S2 favored its inhibition. This suggests that the processing resources for the subsequent stimuli are limited and need to be shared. This sharing of resources appeared to arise from adjustments made on a trial-by-trial basis, in that systematic reaction time prolongations on Go-trials following Stop-trials versus following Go-trials were accompanied by attenuated sensory processing to the Go-stimulus similar to that seen in successful versus unsuccessful stopping in Stop-trials.

Boehler C. N., Schevernels H., Hopf J-M., Stoppel C. M., & Krebs R. M . ( 2014).

Reward prospect rapidly speeds up response inhibition via reactive control

Cognitive Affective & Behavioral Neuroscience, 14( 2), 593-609.

DOI:10.3758/s13415-014-0251-5      URL     PMID:24448735      [本文引用: 4]

Response inhibition is an important cognitive-control function that allows for already-initiated or habitual behavioral responses to be promptly withheld when needed. A typical paradigm to study this function is the stop-signal task. From this task, the stop-signal response time (SSRT) can be derived, which indexes how rapidly an already-initiated response can be canceled. Typically, SSRTs range around 200 ms, identifying response inhibition as a particularly rapid cognitive-control process. Even so, it has recently been shown that SSRTs can be further accelerated if successful response inhibition is rewarded. Since this earlier study effectively ruled out differential preparatory (proactive) control adjustments, the reward benefits likely relied on boosted reactive control. Yet, given how rapidly such control processes would need to be enhanced, alternative explanations circumventing reactive control are important to consider. We addressed this question with an fMRI study by gauging the overlap of the brain networks associated with reward-related and response-inhibition-related processes in a reward-modulated stop-signal task. In line with the view that reactive control can indeed be boosted swiftly by reward availability, we found that the activity in key brain areas related to response inhibition was enhanced for reward-related stop trials. Furthermore, we observed that this beneficial reward effect was triggered by enhanced connectivity between task-unspecific (reward-related) and task-specific (inhibition-related) areas in the medial prefrontal cortex (mPFC). The present data hence suggest that reward information can be translated very rapidly into behavioral benefits (here, within ~200 ms) through enhanced reactive control, underscoring the immediate responsiveness of such control processes to reward availability in general.

Botvinick M.&Braver T., ( 2015).

Motivation and cognitive control: From behavior to neural mechanism

Annual Review of Psychology, 66( 1), 83-113.

DOI:10.1146/annurev-psych-010814-015044      URL     PMID:25251491      [本文引用: 3]

Abstract Research on cognitive control and executive function has long recognized the relevance of motivational factors. Recently, however, the topic has come increasingly to center stage, with a surge of new studies examining the interface of motivation and cognitive control. In the present article we survey research situated at this interface, considering work from cognitive and social psychology and behavioral economics, but with a particular focus on neuroscience research. We organize existing findings into three core areas, considering them in the light of currently vying theoretical perspectives. Based on the accumulated evidence, we advocate for a view of control function that treats it as a domain of reward-based decision making. More broadly, we argue that neuroscientific evidence plays a critical role in understanding the mechanisms by which motivation and cognitive control interact. Opportunities for further cross-fertilization between behavioral and neuroscientific research are highlighted.

Braver T. S., Krug M. K., Chiew K. S., Kool W., Westbrook J. A., Clement N. J., .. Somerville L. H . ( 2014).

Mechanisms of motivation-cognition interaction: Challenges and opportunities

Cognitive Affective & Behavioral Neuroscience, 14( 2), 443-472.

DOI:10.3758/s13415-014-0300-0      URL     PMID:4986920      [本文引用: 2]

Abstract Recent years have seen a rejuvenation of interest in studies of motivation-cognition interactions arising from many different areas of psychology and neuroscience. The present issue of Cognitive, Affective, & Behavioral Neuroscience provides a sampling of some of the latest research from a number of these different areas. In this introductory article, we provide an overview of the current state of the field, in terms of key research developments and candidate neural mechanisms receiving focused investigation as potential sources of motivation-cognition interaction. However, our primary goal is conceptual: to highlight the distinct perspectives taken by different research areas, in terms of how motivation is defined, the relevant dimensions and dissociations that are emphasized, and the theoretical questions being targeted. Together, these distinctions present both challenges and opportunities for efforts aiming toward a more unified and cross-disciplinary approach. We identify a set of pressing research questions calling for this sort of cross-disciplinary approach, with the explicit goal of encouraging integrative and collaborative investigations directed toward them.

Botvinick M., Nystrom L. E., Fissell K., Carter C. S., & Cohen J. D . ( 1999).

Conflict monitoring versus selection- for-action in anterior cingulate cortex

Nature, 402( 785), 179-181.

DOI:10.1038/46035      URL     PMID:10647008      [本文引用: 2]

Reports a study that attempts to determine the role of the anterior cingulate cortex (ACC), located on the medial surface of the frontal lobes of the brain, on the regulation of attention. Theory of attention by which the ACC detects and signals the occurrence of conflicts in information processing; Comparison with the selection-for-action theory; How researchers tested for the conflict-monitoring activity.

Botvinick M. M., Cohen J. D., & Carter C. S . ( 2004).

Conflict monitoring and anterior cingulate cortex: An update

Trends in Cognitive Sciences, 8( 12), 539-546.

DOI:10.1016/j.tics.2004.10.003      URL     PMID:15556023      [本文引用: 1]

One hypothesis concerning the human dorsal anterior cingulate cortex (ACC) is that it functions, in part, to signal the occurrence of conflicts in information processing, thereby triggering compensatory adjustments in cognitive control. Since this idea was first proposed, a great deal of relevant empirical evidence has accrued. This evidence has largely corroborated the conflict-monitoring hypothesis, and some very recent work has provided striking new support for the theory. At the same time, other findings have posed specific challenges, especially concerning the way the theory addresses the processing of errors. Recent research has also begun to shed light on the larger function of the ACC, suggesting some new possibilities concerning how conflict monitoring might fit into the cingulate's overall role in cognition and action.

Carter C. S., Macdonald A. M., Botvinick M., Ross L. L., Stenger V. A., Noll D., & Cohen J. D . ( 2000).

Parsing executive processes: Strategic vs. evaluative functions of the anterior cingulate cortex

Proceedings of the National Academy of Sciences of the United States of America, 97( 4), 1944-1948.

DOI:10.1073/pnas.97.4.1944      URL     [本文引用: 1]

Chikazoe J., Jimura K., Asari T., Yamashita K. L., Morimoto H., Hirose S., … Konishi S . ( 2009).

Functional dissociation in right inferior frontal cortex during performance of go/no-go task

Cerebral Cortex, 19( 1), 146-152.

DOI:10.1093/cercor/bhn065      URL     PMID:18445602      [本文引用: 1]

Abstract The contribution of the right inferior frontal cortex to response inhibition has been demonstrated by previous studies of neuropsychology, electrophysiology, and neuroimaging. The inferior frontal cortex is also known to be activated during processing of infrequent stimuli such as stimulus-driven attention. Response inhibition has most often been investigated using the go/no-go task, and the no-go trials are usually given infrequently to enhance prepotent response tendency. Thus, it has not been clarified whether the inferior frontal activation during the go/no-go task is associated with response inhibition or processing of infrequent stimuli. In the present functional magnetic resonance imaging study, we employed not only frequent-go trials but also infrequent-go trials that were presented as infrequently as the no-go trials. The imaging results demonstrated that the posterior inferior frontal gyrus (pIFG) was activated during response inhibition as revealed by the no-go vs. infrequent-go trials, whereas the inferior frontal junction (IFJ) region was activated primarily during processing of infrequent stimuli as revealed by the infrequent-go versus frequent-go trials. These results indicate that the pIFG and IFJ within the inferior frontal cortex are spatially close but are associated with different cognitive control processes in the go/no-go paradigm.

Derntl B.&Habel U., ( 2016).

Angry but not neutral faces facilitate response inhibition in schizophrenia patients

European Archives of Psychiatry and Clinical Neuroscience, 267( 7), 621-627.

DOI:10.1007/s00406-016-0748-8      URL     PMID:27866272      [本文引用: 1]

Schizophrenia is a very heterogeneous disorder with extensive impairments in cognitive as well as emotional abilities. One critical domain is response inhibition, and previous studies in schizophrenia patients have mostly observed impairments, i.e., slower inhibition. Moreover, response inhibition to socially salient stimuli has not been investigated in schizophrenia so far. Therefore, to elucidate emotion-cognition interactions by examining potential emotional effects on inhibition processes and further investigate the association of cognition with inhibition we used an emotional stop signal task in 27 schizophrenia patients and 27 gender- and age-matched controls. Task irrelevant emotional faces (angry and neutral) were used as stimuli in a stop signal reaction time task. Regarding accuracy, patients showed significantly worse performance in neutral trials, while their performance in anger trials (stop and go) was similar to controls. Angry faces elicited faster response inhibition in both groups, underlining an emotional facilitation effect. Neurocognitive functions significantly correlated with accuracy in the stop signal task in schizophrenia patients, thus further strengthening the notion of the strong link between cognitive abilities and inhibition processes. Inhibitory control impairments are of high clinical interest due to their association with substance abuse, impulsive behavior and suicide. Based on our data, neutral faces significantly affect response inhibition in schizophrenia while an emotional facilitation effect was apparent for angry faces even in schizophrenia patients. Thus, our data further support the notion that neutral face processing is critically impaired in schizophrenia.

Egner T.&Hirsch J., ( 2005).

Cognitive control mechanisms resolve conflict through cortical amplification of task-relevant information

Nature Neuroscience, 8( 12), 1784-1790

DOI:10.1038/nn1594      URL     PMID:16286928      [本文引用: 1]

Abstract A prominent model of how the brain regulates attention proposes that the anterior cingulate cortex monitors the occurrence of conflict between incompatible response tendencies and signals this information to a cognitive control system in dorsolateral prefrontal cortex. Cognitive control is thought to resolve conflict through the attentional biasing of perceptual processing, emphasizing task-relevant stimulus information. It is not known, however, whether conflict resolution is mediated by amplifying neural representations of task-relevant information, inhibiting representations of task-irrelevant information, or both. Here we manipulated trial-by-trial levels of conflict and control during a Stroop task using face stimuli, while recording hemodynamic responses from human visual cortex specialized for face processing. We show that, in response to high conflict, cognitive control mechanisms enhance performance by transiently amplifying cortical responses to task-relevant information rather than by inhibiting responses to task-irrelevant information. These results implicate attentional target-feature amplification as the primary mechanism for conflict resolution through cognitive control.

Erika-Florence M., Leech R., & Hampshire A . ( 2014).

A functional network perspective on response inhibition and attentional control

Nature Communications, 5( 5), 4073.

DOI:10.1038/ncomms5073      URL     PMID:4059922      [本文引用: 1]

Inferior frontal cortex (IFC) modules that inhibit dominant behaviours are a popular feature in theories of cognitive dysfunction. However, the paradigms on which these theories are based fail to distinguish between inhibitory and non-inhibitory cognitive demands. Here we use four novel fMRI variants of the classic stop-signal task to test whether the IFC houses unique inhibitory modules. Our results demonstrate that IFC sub-regions are not functionally unique in their sensitivities to inhibitory cognitive demands, but instead form components of spatially distributed networks. These networks are most strongly activated when infrequent stimuli are being processed, regardless of behavioural inhibitory demands, and when novel tasks are being acquired, as opposed to when routine responses must be suppressed. We propose that there are no inhibitory modules within the frontal lobes and that behavioural inhibition is an emergent property of spatially distributed functional networks, each of which supports a broader class of cognitive demands.

Freeman S.M., & Aron A.R . ( 2016).

Withholding a reward-driven action: Studies of the rise and fall of motor activation and the effect of cognitive depletion

Journal of Cognitive Neuroscience, 28( 2), 237-251.

DOI:10.1162/jocn_a_00893      URL     PMID:5208043      [本文引用: 2]

Abstract Controlling an inappropriate response tendency in the face of a reward-predicting stimulus likely depends on the strength of the reward-driven activation, the strength of a putative top-down control process, and their relative timing. We developed a rewarded go/no-go paradigm to investigate such dynamics. Participants made rapid responses (on go trials) to high versus low reward-predicting stimuli and sometimes had to withhold responding (on no-go trials) in the face of the same stimuli. Behaviorally, for high versus low reward stimuli, responses were faster on go trials, and there were more errors of commission on no-go trials. We used single-pulse TMS to map out the corticospinal excitability dynamics, especially on no-go trials where control is needed. For successful no-go trials, there was an early rise in motor activation that was then sharply reduced beneath baseline. This activation-reduction pattern was more pronounced for high- versus low-reward trials and in individuals with greater motivational drive for reward. A follow-on experiment showed that, when participants were fatigued by an effortful task, they made more errors on no-go trials for high versus low reward stimuli. Together, these studies show that, when a response is inappropriate, reward-predicting stimuli induce early motor activation, followed by a top-down effortful control process (which we interpret as response suppression) that depends on the strength of the preceding activation. Our findings provide novel information about the activation-suppression dynamics during control over reward-driven actions, and they illustrate how fatigue or depletion leads to control failures in the face of reward.

Freeman S. M., Razhas L., & Aron A. R . ( 2014).

Top-down response suppression mitigates action tendencies triggered by a motivating stimulus

Current Biology, 24( 2), 212-216.

DOI:10.1016/j.cub.2013.12.019      URL     PMID:4396623      [本文引用: 1]

Freeman et02al. investigate how action tendencies generated by a motivating stimulus are controlled. They find that such control can be implemented via top-down response suppression and that this response suppression is selective to the effector that can obtain reward.

Hampshire A., & Sharp D.J . ( 2015).

Contrasting network and modular perspectives on inhibitory control

Trends in Cognitive Sciences, 19( 8), 445-452.

DOI:10.1016/j.tics.2015.06.006      URL     PMID:26160027      [本文引用: 2]

A prominent theory proposes that the right inferior frontal cortex of the human brain houses a dedicated region for motor response inhibition. However, there is growing evidence to support the view that this inhibitory control hypothesis is incorrect. Here, we discuss evidence in favour of our alternative hypothesis, which states that response inhibition is one example of a broader class of control processes that are supported by the same set of frontoparietal networks. These domain-general networks exert control by modulating local lateral inhibition processes, which occur ubiquitously throughout the cortex. We propose that to fully understand the neural basis of behavioural control requires a more holistic approach that considers how common network mechanisms support diverse cognitive processes.

Hickey C., & Peelen M.V . ( 2015).

Neural mechanisms of incentive salience in naturalistic human vision

Neuron, 85( 3), 512-518.

DOI:10.1016/j.neuron.2014.12.049      URL     PMID:25654257      [本文引用: 2]

Hickey and Peelen show that examples of reward-associated object categories involuntarily draw attention when presented in scenes. Activity in the midbrain predicts the quality of representation in visual cortex for these objects, demonstrating how real-world perception is guided by value.

Jiang J., Xiang L., Zhang Q. L., & Chen A. T . ( 2014).

Conflict adaptation is independent of consciousness: Behavioral and ERP evidence

Acta Psychologica Sinica, 46( 5), 581-592.

[本文引用: 1]

[ 蒋军, 向玲, 张庆林, 陈安涛 . ( 2014).

冲突适应独立于意识: 来自行为和ERP的证据

心理学报,46( 5), 581-592.]

DOI:10.3724/SP.J.1041.2014.00581      URL     [本文引用: 1]

Previous studies have suggested that some cognitive control functions such as inhibition control and task switching were independent of consciousness, but it is unclear whether consciousness is necessary for conflict adaptation. Prior studies in consciousness domain showed that conflict adaptation reflected on behavioral measures and ERP components (N2 and P3). The purpose of current study is to test whether consciousness is necessary for conflict control. If conflict control was independent of consciousness, we would observe that the conflict effect indexed on reaction times and N2 and P3 amplitude modulated by previous trial congruency regardless of consciousness. If these hypotheses were verified, it could deepen our understanding of unconscious information processing and give us insight into the function of consciousness. To test our hypotheses, we obtained the behavioral and electroencephalogram (EEG) data from 18 subjects using an arrow version meta-contrast masking task, in which the primes fitted exactly within the inner contour of the target. By manipulating the time interval of prime and target and the presentation time of primes, the prime can be weakly or strongly masked. One subject was excluded from further analysis due to too many artifacts. To exclude the alternative interpretation of conflict adaptation by stimulus/response repetitions, stimulus or (and) response repetitions trials were removed before further analysis. After removing the artifacts included in the EEG segments, the ERPs were obtained according to each condition. The negative peak of N2 was averaged during 240-320 ms across fronto-central ROI electrode sites, while the P3 was averaged during the time 350-500 ms across centro-parietal ROI electrode sites. All analyses were performed separately based on the conditions of consciousness. The results showed that there was reliable conflict effect on reaction times and N2 and P3 amplitudes under conscious and unconscious conditions, and these effects were modulated by the congruency of previous trial type. Specifically, the conflict effect is smaller when the previous trials were incongruent than when they were congruent. Nevertheless, the size of conflict adaptation effect indexed on reaction times and N2 amplitude were larger under conscious condition than under unconscious condition, while the size of conflict adaptation between conscious and unconscious conditions were not significant. To our knowledge, we are the first to use ERP methods to study whether consciousness is necessary for conflict adaptation. These results not only suggest that the unconscious experience has great impact on human information processing system, but also suggest that conflict control is independent of consciousness. The difference in magnitude of conflict adaptation effect may come from the magnitude difference of conflict effect, and conscious conflict is far larger than unconscious conflict. Thus, in further studies we should pay attention to the difference and common aspects on unconscious and conscious conflict control. Moreover, the conflict monitoring theory can be perfectly interpreted the conflict control, but it do not elucidate the function of consciousness in the loop of conflict control. In conclusion, the current findings indicate that conflict adaptation is independent of consciousness. The current study could give some insights to understand and reveal the function of consciousness as well as its effect on conflict control.

Kerns J. G., Cohen J. D., MacDonald Ⅲ, A. W.., Cho R. Y.., Stenger V. A., & Carter C. S . ( 2004).

Anterior cingulate conflict monitoring and adjustments in control

Science, 303( 5660), 1023-1026.

DOI:10.1126/science.1089910      URL     [本文引用: 1]

Krawczyk D. C., Gazzaley A., & D'Esposito M . ( 2007).

Reward modulation of prefrontal and visual association cortex during an incentive working memory task

Brain Research, 1141( 4), 168-177.

DOI:10.1016/j.brainres.2007.01.052      URL     PMID:17320835      [本文引用: 1]

Cognitive performance differs with motivation, but little direct evidence exists regarding the neural mechanisms of the influence of reward motivation on working memory (WM). We tested the effects of motivation on the top-down control in visual WM. Encoding relevant stimuli for maintenance, while suppressing inappropriate inputs is considered a core process in cognition. Prior functional magnetic resonance imaging (fMRI) results demonstrated that stimulus-specific visual association cortex serves as a marker of activation differences for task-relevant and task-irrelevant inputs, such that enhanced activity occurs when attention is directed to relevant stimuli and suppressed activity occurs when attention is directed away from irrelevant stimuli [Gazzaley, A., Cooney, J., McEvoy, K., Knight, R.T., and D'Esposito, M. J. Cogn. Neurosci. 17, 507 517]. We used fMRI to test whether differential WM performance, indexed by lowered response times on a delayed-recognition task, was associated with amplification of enhancement and suppression effects during stimulus encoding within visual association cortex. Our results indicate that enhancement and suppression are amplified for trials with the highest reward level relative to non-rewarded trials for a scene-selective cortical region. In a face-selective region, similar modulation of enhancement for the highest reward level relative to non-rewarded trials was found. Prefrontal cortex also showed enhanced activity during high reward trials. Overall these results reveal that reward motivation can play a pivotal role in driving performance through top-down signaling in frontal regions involved in WM, as well as visual association regions selective to processing the perceptual inputs of the items to be remembered.

Krebs R. M., Boehler C. N., Appelbaum L. G., & Woldorff M. G . ( 2013).

Reward associations reduce behavioral interference by changing the temporal dynamics of conflict processing

PLoS One, 8( 1), e53894.

DOI:10.1371/journal.pone.0053894      URL     PMID:3542315      [本文引用: 2]

Associating stimuli with the prospect of reward typically facilitates responses to those stimuli due to an enhancement of attentional and cognitive-control processes. Such reward-induced facilitation might be especially helpful when cognitive-control mechanisms are challenged, as when one must overcome interference from irrelevant inputs. Here, we investigated the neural dynamics of reward effects in a color-naming Stroop task by employing event-related potentials (ERPs). We found that behavioral facilitation in potential-reward trials, as compared to no-reward trials, was paralleled by early ERP modulations likely indexing increased attention to the reward-predictive stimulus. Moreover, reward changed the temporal dynamics of conflict-related ERP components, which may be a consequence of an early access to the various stimulus features and their relationships. Finally, although word meanings referring to potential-reward colors were always task-irrelevant, they caused greater interference compared to words referring to no-reward colors, an effect that was accompanied by a relatively early fronto-central ERP modulation. This latter observation suggests that task-irrelevant reward information can undermine goal-directed behavior at an early processing stage, presumably reflecting priming of a goal-incompatible response. Yet, these detrimental effects of incongruent reward-related words were absent in potential-reward trials, apparently due to the prioritized processing of task-relevant reward information. Taken together, the present data demonstrate that reward associations can influence conflict processing by changing the temporal dynamics of stimulus processing and subsequent cognitive-control mechanisms.

Krebs R. M., Boehler C. N., Egner T., & Woldorff M. G . ( 2011).

The neural underpinnings of how reward associations can both guide and misguide attention

Journal of Neuroscience, 31( 26), 9752-9759.

DOI:10.1523/JNEUROSCI.0732-11.2011      URL     PMID:3142621      [本文引用: 7]

It is commonly accepted that reward is an effective motivator of behavior, but little is known about potential costs resulting from reward associations. Here, we used functional magnetic resonance imaging (fMRI) to investigate the neural underpinnings of such reward-related performance-disrupting effects in a reward-modulated Stroop task in humans. While reward associations in the task-relevant dimension (i.e., ink color) facilitated performance, behavioral detriments were found when the task-irrelevant dimension (i.e., word meaning) implicitly referred to reward-predictive ink colors. Neurally, only relevant reward associations invoked a typical reward-anticipation response in the nucleus accumbens (NAcc), which was in turn predictive of behavioral facilitation. In contrast, irrelevant reward associations increased activity in a medial prefrontal motor-control-related region, namely the presupplementary motor area (pre-SMA), which likely reflects the preemption and inhibition of automatic response tendencies that are amplified by irrelevant reward-related words. This view was further supported by a positive relationship between pre-SMA activity and pronounced response slowing in trials containing reward-related as compared with reward-unrelated incongruent words. Importantly, the distinct neural processes related to the beneficial and detrimental behavioral effects of reward associations appeared to arise from preferential-coding mechanisms in visual-processing areas that were shared by the two stimulus dimensions, suggesting a transfer of reward-related saliency to the irrelevant dimension, but with highly differential behavioral and neural ramifications. More generally, the data demonstrate that even entirely irrelevant reward associations can influence stimulus-processing and response-selection pathways relatively automatically, thereby representing an important flipside of reward-driven performance enhancements.

Krebs R. M., Boehler C. N., Roberts K. C., Song A. W., & Woldorff M. G . ( 2012).

The involvement of the dopaminergic midbrain and cortico-striatal-thalamic circuits in the integration of reward prospect and attentional task demands

Cerebral Cortex, 22( 3), 607-615.

DOI:10.1093/cercor/bhr134      URL     PMID:21680848      [本文引用: 1]

Reward has been shown to promote performance in multiple task domains. However, an important debate has developed about the uniqueness of reward-related neural signatures associated with such facilitation, as similar neural patterns can be triggered by increased attentional focus independent of reward. Here, we used functional magnetic resonance imaging to directly investigate the neural commonalities and interactions between the anticipation of both reward and task difficulty, by independently manipulating these factors in a cued-attention paradigm. In preparation for the target stimulus, both factors increased activity within the midbrain, dorsal striatum, and fronto-parietal areas, while inducing deactivations in default-mode regions. Additionally, reward engaged the ventral striatum, posterior cingulate, and occipital cortex, while difficulty engaged medial and dorsolateral frontal regions. Importantly, a network comprising the midbrain, caudate , thalamus, and anterior midcingulate cortex exhibited an interaction between reward and difficulty, presumably reflecting additional resource recruitment for demanding tasks with profitable outcome. This notion was consistent with a negative correlation between cue-related midbrain activity and difficulty-induced performance detriments in reward-predictive trials. Together, the data demonstrate that expected value and attentional demands are integrated in cortico-striatal-thalamic circuits in coordination with the dopaminergic midbrain to flexibly modulate resource allocation for an effective pursuit of behavioral goals.

Krebs R. M., Boehler C. N., & Woldorff M. G . ( 2010).

The influence of reward associations on conflict processing in the Stroop task

Cognition, 117( 3), 341-347.

DOI:10.1016/j.cognition.2010.08.018      URL     PMID:2967668      [本文引用: 1]

Performance in a behavioral task can be facilitated by associating stimulus properties with reward. In contrast, conflicting information is known to impede task performance. Here we investigated how reward associations influence the within-trial processing of conflicting information using a color-naming Stroop task in which a subset of ink colors (task-relevant dimension) was associated with monetary incentives. We found that color-naming performance was enhanced on trials with potential-reward versus those without. Moreover, in potential-reward trials, typical conflict-induced performance decrements were attenuated if the incongruent word (task-irrelevant dimension) was unrelated to reward. In contrast, incongruent words that were semantically related to reward-predicting ink colors interfered with performance in potential-reward trials and even more so in no-reward trials, despite the semantic meaning being entirely task-irrelevant. These observations imply that the prospect of reward enhances the processing of task-relevant stimulus information, whereas incongruent reward-related information in a task-irrelevant dimension can impede task performance.

Lee H. W., Lu M-S., Chen C-Y., Muggleton N. G., Hsu T-Y., & Juan C-H . ( 2016).

Roles of the pre-SMA and rIFG in conditional stopping revealed by transcranial magnetic stimulation

Behavioural Brain Research, 296, 459-467.

DOI:10.1016/j.bbr.2015.08.024      URL     PMID:26304720      [本文引用: 1]

Although both the presupplementary motor area (pre-SMA) and the right inferior frontal gyrus (rIFG) have been demonstrated to be critical for response inhibition, there is still considerable disagreement over the roles they play in the process. In the present study, we investigated the causal relations of the pre-SMA and the rIFG in a conditional stop-signal task by applying offline theta-burst transcranial magnetic stimulation. The task introduced a continue condition, which requires the same motor response as in a go trial but captures attention as in a stop trial. We found great individual differences in the amount of slowing on continue trials. Temporary suppression of pre-SMA activity prolonged the continue RT in participants who slowed little in response to continue trials, whereas disruption of the rIFG did not lead to significant changes in performance irrespective of the degree of slowing. Our results contribute to the understanding of the role of the pre-SMA by providing causal evidence that it is involved in response slowing on continue trials during conditional stopping, and it is likely that its efficiency in updating motor planning and reinitiating an inhibited response was associated with the amount of slowing.

Leotti L.A., & , Wager T.D . ( 2010).

Motivational influences on response inhibition measures

Journal of Experimental Psychology: Human Perception and Performance, 36( 2), 430-447.

DOI:10.1037/a0016802      URL     PMID:3983778      [本文引用: 1]

Response inhibition ability is commonly assessed using the stop-signal paradigm, which provides a sensitive and reliable measure of inhibitory ability: stop-signal reaction time (SSRT). SSRT is based on a simple 'race' model, which asserts that on a given stop-signal trial, a "go-process," involving target identification, motor planning, and response initiation, races against a "stop-process," involving stop-signal target identification and motor planning processes. SSRT is assumed to reflect a trait ability that is independent of contextual influences, such as strategic or motivational bias. However, in the stop-signal task, there is a basic tradeoff between responding quickly on "go" trials and correctly withholding a response on "stop" trials. It is unknown whether motivational

Logan G.D., & Cowan W.B . ( 1984).

On the ability to inhibit thought and action: A theory of an act of control

Psychological Review, 91( 3), 295-327.

DOI:10.1037/0033-295x.91.3.295      URL     [本文引用: 1]

Navalpakkam V.&Treisman A., ( 2010).

Optimal reward harvesting in complex perceptual environment

Proceedings of the National Academy of Sciences of the United States of America, 107( 11), 5232-5237.

DOI:10.1073/pnas.0911972107      URL     PMID:20194768      [本文引用: 1]

The ability to choose rapidly among multiple targets embedded in a complex perceptual environment is key to survival. Targets may differ in their reward value as well as in their low-level perceptual properties (e.g., visual saliency). Previous studies investigated separately the impact of either value or saliency on choice; thus, it is not known how the brain combines these two variables during decision making. We addressed this question with three experiments in which human subjects attempted to maximize their monetary earnings by rapidly choosing items from a brief display. Each display contained several worthless items (distractors) as well as two targets, whose value and saliency were varied systematically. We compared the behavioral data with the predictions of three computational models assuming that (i) subjects seek the most valuable item in the display, (ii) subjects seek the most easily detectable item, and (iii) subjects behave as an ideal Bayesian observer who combines both factors to maximize the expected reward within each trial. Regardless of the type of motor response used to express the choices, we find that decisions are influenced by both value and feature-contrast in a way that is consistent with the ideal Bayesian observer, even when the targets' feature-contrast is varied unpredictably between trials. This suggests that individuals are able to harvest rewards optimally and dynamically under time pressure while seeking multiple targets embedded in perceptual clutter.

Pawliczek C. M., Derntl B., Kellermann T., Kohn N., Gur R. C., & Habel U . ( 2013).

Inhibitory control and trait aggression: Neural and behavioral insights using the emotional stop signal task

Neuroimage, 79( 6), 264-274.

DOI:10.1016/j.neuroimage.2013.04.104      URL     PMID:23660028      [本文引用: 1]

61Emotional response inhibition in males with high (HA) and low (LA) trait aggression61Poorer response inhibition in HA was associated with higher motoric impulsivity.61HA revealed attenuated activity in brain regions associated to response inhibition.61Response inhibition improved during emotional (anger) trials in both groups.61Higher activity during anger trials in bilateral fusiform, SMA and limbic regions

Pessoa L. ( 2009).

How do emotion and motivation direct executive control?

Trends in Cognitive Sciences, 13( 4), 160-166.

DOI:10.1016/j.tics.2009.01.006      URL     PMID:19285913      [本文引用: 3]

Emotion and motivation have crucial roles in determining human behavior. Yet, how they interact with cognitive control functions is less understood. Here, the basic elements of a conceptual framework for understanding how they interact are introduced. More broadly, the ‘dual competition’ framework proposes that emotion and motivation affect both perceptual and executive competition. In particular, the anterior cingulate cortex is hypothesized to be engaged in attentional/effortful control mechanisms and to interact with several other brain structures, including the amygdala and nucleus accumbens, in integrating affectively significant signals with control signals in prefrontal cortex. An implication of the proposal is that emotion and motivation can either enhance or impair behavioral performance depending on how they interact with control functions.

Pessoa L., & Engelmann J.B . ( 2010).

Embedding reward signals into perception and cognition

Frontiers in Neuroscience, 4( 17), 4-17.

DOI:10.3389/fnins.2010.00017      URL     PMID:2940450      [本文引用: 1]

Despite considerable interest in the neural basis of valuation, the question of how valuation affects cognitive processing has received relatively less attention. Here, we review evidence from recent behavioral and neuroimaging studies supporting the notion that motivation can enhance perceptual and executive control processes to achieve more efficient goal-directed behavior. Specifically, in the context of cognitive tasks offering monetary gains, improved behavioral performance has been repeatedly observed in conjunction with elevated neural activations in task-relevant perceptual, cognitive and reward-related regions. We address the neural basis of motivation-cognition interactions by suggesting various modes of communication between relevant neural networks: (1) global hub regions may integrate information from multiple inputs providing a communicative link between specialized networks; (2) point-to-point interactions allow for more specific cross-network communication; and (3) diffuse neuromodulatory systems can relay motivational signals to cortex and enhance signal processing. Together, these modes of communication allow information regarding motivational significance to reach relevant brain regions and shape behavior.

Salinas E., & Stanford T.R . ( 2013).

The countermanding task revisited: Fast stimulus detection is a key determinant of psychophysical performance

Journal of Neuroscience, 33( 13), 5668-5685.

DOI:10.1523/JNEUROSCI.3977-12.2013      URL     PMID:3650622      [本文引用: 2]

Abstract The countermanding task is a standard method for assessing cognitive/inhibitory control over action and for investigating its neural correlates. In it, the subject plans a movement and either executes it, if no further instruction is given, or attempts to prevent it, if a stop signal is shown. Through various experimental manipulations, many studies have sought to characterize the inhibitory mechanisms thought to be at work in the task, typically using an inferred, model-dependent metric called the stop-signal reaction time. This approach has consistently overlooked the impact of perceptual evaluation on performance. Through analytical work and computer simulations, here we show that psychophysical performance in the task can be easily understood as the result of an ongoing motor plan that is modified (decelerated) by the outcome of a rapid sensory detection process. Notably, no specific assumptions about hypothetical inhibitory mechanisms are needed. This modeling framework achieves four things: (1) it replicates and reconciles behavioral results in numerous variants of the countermanding task; (2) it provides a new, objective metric for characterizing task performance that is more effective than the stop-signal reaction time; (3) it shows that the time window over which detection of a high-visibility stimulus effectively occurs is extremely short ( 20 ms); and (4) it indicates that modulating neuronal latencies and the buildup rates of developing motor plans are two key neural mechanisms for controlling action. The results suggest that manipulations of the countermanding task often cause changes in perceptual detection processes, and not necessarily in inhibition.

Schevernels H., Bombeke K., Van der Borght L., Hopf J-M., Krebs R. M., & Boehler C. N . ( 2015).

Electrophysiological evidence for the involvement of proactive and reactive control in a rewarded stop-signal task

Neuroimage, 121, 115-125.

DOI:10.1016/j.neuroimage.2015.07.023      URL     PMID:26188262      [本文引用: 3]

Highlights 61 Response inhibition benefits from a simple stimulus–reward association. 61 Inhibition-related components are larger and peak earlier in reward-related trials. 61 Accompanying this, visual attention to the reward-related stop signal is enhanced. 61 Go-stimulus processing but not response inhibition is boosted by reward context. Abstract Reward availability is known to facilitate various cognitive operations, which is usually studied in cue-based paradigms that allow for enhanced preparation in reward-related trials. However, recent research using tasks that signal reward availability via task-relevant stimuli suggests that reward can also rapidly promote performance independent of global strategic preparation. Notably, this effect was also observed in a reward-related stop-signal task, in which behavioral measures of inhibition speed were found to be shorter in trials signaling reward. Corresponding fMRI results implied that this effect relies on boosted reactive control as indicated by increased activity in the ‘inhibition-related network’ in the reward-related condition. Here, we used EEG to better characterize transient modulations of attentional processes likely preceding this ultimate implementation of response inhibition. Importantly, such modulations would probably reflect enhanced proactive control in the form of more top-down attention to reward-related features. Counter to the notion that behavioral benefits would rely purely on reactive control, we found increased stop-evoked attentional processing (larger N1 component) on reward-related trials. This effect was accompanied by enhanced frontal P3 amplitudes reflecting successful stopping, and earlier and larger ERP differences between successful and failed stop trials in the reward-related condition. Finally, more global proactive control processes in the form of a reward context modulation of reward-unrelated trials did not have an effect on stopping performance but did influence attentional processing of go stimuli. Together, these results suggest that proactive and reactive processes can interact to bring about stimulus-specific reward benefits when the task precludes differential global preparation.

Sharp D. J., Bonnelle V., De Boissezon X., Beckmann C. F., James S. G., Patel M. C., & Mehta M. A . ( 2010).

Distinct frontal systems for response inhibition, attentional capture, and error processing

Proceedings of the National Academy of Sciences of the United States of America, 107( 13), 6106-6111.

DOI:10.1073/pnas.1000175107      URL     PMID:20220100      [本文引用: 2]

Stopping an action in response to an unexpected event requires both that the event is attended to, and that the action is inhibited. Previous neuroimaging investigations of stopping have failed to adequately separate these cognitive elements. Here we used a version of the widely used Stop Signal Task that controls for the attentional capture of stop signals. This allowed us to fractionate the contributions of frontal regions, including the right inferior frontal gyrus and medial frontal cortex, to attentional capture, response inhibition, and error processing. A ventral attentional system, including the right inferior frontal gyrus, has been shown to respond to unexpected stimuli. In line with this evidence, we reasoned that lateral frontal regions support attentional capture, whereas medial frontal regions, including the presupplementary motor area (pre-SMA), actually inhibit the ongoing action. We tested this hypothesis by contrasting the brain networks associated with the presentation of unexpected stimuli against those associated with outright stopping. Functional MRI images were obtained in 26 healthy volunteers. Successful stopping was associated with activation of the right inferior frontal gyrus, as well as the pre-SMA. However, only activation of the pre-SMA differentiated stopping from a high-level baseline that controlled for attentional capture. As expected, unsuccessful attempts at stopping activated the anterior cingulate cortex. In keeping with work in nonhuman primates these findings demonstrate that successful motor inhibition is specifically associated with pre-SMA activation.

Tang D.D., & Chen A.T . ( 2013).

Neural oscillation mechanisms of conflict adaptation

Scientia Sinica Vitae, 43( 11), 992-1002.

[本文引用: 1]

[ 唐丹丹, 陈安涛 . ( 2013).

冲突适应的神经振荡机制

中国科学:生命科学, 43( 11), 992-1002.]

[本文引用: 1]

van den Berg B., Krebs R. M., Lorist M. M., & Woldorff M. G . ( 2014).

Utilization of reward-prospect enhances preparatory attention and reduces stimulus conflict

Cognitive Affective & Behavioral Neuroscience, 14( 2), 561-577.

DOI:10.3758/s13415-014-0281-z      URL     PMID:24820263      [本文引用: 1]

Abstract The prospect of gaining money is an incentive widely at play in the real world. Such monetary motivation might have particularly strong influence when the cognitive system is challenged, such as when needing to process conflicting stimulus inputs. Here, we employed manipulations of reward-prospect and attentional-preparation levels in a cued-Stroop stimulus conflict task, along with the high temporal resolution of electrical brain recordings, to provide insight into the mechanisms by which reward-prospect and attention interact and modulate cognitive task performance. In this task, the cue indicated whether or not the participant needed to prepare for an upcoming Stroop stimulus and, if so, whether there was the potential for monetary reward (dependent on performance on that trial). Both cued attention and cued reward-prospect enhanced preparatory neural activity, as reflected by increases in the hallmark attention-related negative-polarity ERP slow wave (contingent negative variation [CNV]) and reductions in oscillatory Alpha activity, which was followed by enhanced processing of the subsequent Stroop stimulus. In addition, similar modulations of preparatory neural activity (larger CNVs and reduced Alpha) predicted shorter versus longer response times (RTs) to the subsequent target stimulus, consistent with such modulations reflecting trial-to-trial variations in attention. Particularly striking were the individual differences in the utilization of reward-prospect information. In particular, the size of the reward effects on the preparatory neural activity correlated across participants with the degree to which reward-prospect both facilitated overall task performance (shorter RTs) and reduced conflict-related behavioral interference. Thus, the prospect of reward appears to recruit attentional preparation circuits to enhance processing of task-relevant target information.

van Steenbergen H., Band G. P. H., & Hommel B . ( 2012).

Reward valence modulates conflict-driven attentional adaptation: Electrophysiological evidence

Biological Psychology, 90( 3), 234-241.

DOI:10.1016/j.biopsycho.2012.03.018      URL     PMID:22504294      [本文引用: 1]

Recent findings suggest that, relative to negative feedback, positive feedback counteracts conflict processing and subsequent attentional adaptation. Here we hypothesize that this interaction may direct adjustments in perception and action via the anterior cingulate cortex (ACC). We recorded EEG while participants performed an arrow flanker task with monetary gain or loss as arbitrary reward feedback between trials. As predicted, we found a reduction in conflict-driven adaptation for trials in which conflict was followed by monetary gain (vs. monetary loss), a behavioral effect accompanied by a modulation in early visual processing related to the processing of the distracters. Moreover, time-frequency analyses showed that ongoing fronto-central theta oscillations induced by previous conflict sustained longer after loss than after gain, an interaction presumably reflecting ACC modulation. These data provide a first important step toward understanding the neural mechanism underlying the affective regulation of conflict-driven behavior.

Verbruggen F., Chambers C. D., & Logan G. D . ( 2013).

Fictitious inhibitory differences: How skewness and slowing distort the estimation of stopping latencies

Psychological Science, 24( 3), 352-362.

DOI:10.1177/0956797612457390      URL     [本文引用: 1]

Wang X. P., Zhao X. Y., Xue G., & Chen A. T . ( 2016).

Alertness function of thalamus in conflict adaptation

Neuroimage, 132, 274-282.

DOI:10.1016/j.neuroimage.2016.02.048      URL     PMID:26908318      [本文引用: 1]

61Color backgrounds modulate alertness level;61Blue eliminates conflict adaptation effect (CAE), while red and gray facilitate it;61The alertness function of thalamus is determinant to conflict adaptation;61Coupling between thalamus and inferior frontal cortex underpins color-modulated CAE.

Westbrook A., & Braver T.S . ( 2016).

Dopamine does double duty in motivating cognitive effort

Neuron, 89( 4), 695-710.

DOI:10.1016/j.neuron.2015.12.029      URL     PMID:26889810      [本文引用: 3]

Temporally extended, goal-directed behavior often involves subjectively effortful cognition. Westbrook and Braver review two broad, complementary roles by which DA translates incentive information into cognitive motivation: (1) modulating working memory circuit parameters and (2) training decision value functions for cognitive engagement.

Xu K. Z., Anderson B. A., Emeric E. E., Sali A. W., Stuphorn V., Yantis S., & Courtney S. M . ( 2017).

Neural basis of cognitive control over movement inhibition: Human fMRI and primate electrophysiology evidence

Neuron, 96( 6), 1447-1458.

DOI:10.1016/j.neuron.2017.11.010      URL     PMID:29224723      [本文引用: 1]

Executive control involves the ability to flexibly inhibit or change an action when it is contextually inappropriate. Using the complimentary techniques of human fMRI and monkey electrophysiology in a context-dependent stop signal task, we found a functional double dissociation between the right ventrolateral prefrontal cortex (rVLPFC) and the bi-lateral frontal eye field (FEF). Different regions of rVLPFC were associated with context-based signal meaning versus intention to inhibit a response, while FEF activity corresponded to success or failure of the response inhibition regardless of the stimulus response mapping or the context. These results were validated by electrophysiological recordings in rVLPFC and FEF from one monkey. Inhibition of a planned behavior is therefore likely not governed by a single brain system as had been previously proposed, but instead depends on two distinct neural processes involving different sub-regions of the rVLPFC and their interactions with other motor-related brain regions.

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