Neurophysiological Marker of Visual Working Memory Manipulation
Neurophysiological Marker of Visual Working Memory Manipulation
复制标题
视觉工作记忆操纵的神经生理学标志
DOI：
10.1167/17.10.1116
复制
发表时间：
2017
影响因子：
1.8
通讯作者：
G. Alvarez
中科院分区：
文献类型：
--
作者：
Hrag Pailian;Viola S. Störmer;G. Alvarez
以往的研究已经发现了视觉工作记忆存储容量的神经相关性（例如，Vogel & Machizawa，2004），但没有发现工作记忆的定义特征-存储信息的操作的神经相关性。为此，我们使用脑电图（EEG）记录神经活动，而观察员完成了工作记忆（WM）操纵任务。观察者被提示记住显示器一侧的3个彩色圆圈（忽略另一侧的感知匹配显示器），然后是一个维持期，其中颜色消失，留下占位符。这些事件之后是一个占位符运动期，在此期间，一对占位符进行平稳运动以交换位置。观察者被指示更新空间特征绑定，使特征与移动的占位符保持对齐（存储和操作），或者完全忽略移动并记住原始位置的特征（仅存储）。观察者随后确定了提示项目的颜色。在占位符运动（代表信息的初始存储）之前的初始维护期间，我们观察到两种情况下后电极部位的持续对侧延迟活动（CDA）。这种偏侧活动持续到占位符运动期，并在整个时间窗内保持活跃。在初始维护期间，更新和忽略条件之间的CDA幅度没有差异，F（1，11）= 2.31，p=。16，或占位符运动周期，F（1，11）= 3.69，p=. 08.然而，我们观察到在占位符运动期间，在额中央电极部位，更新试验而不是忽略试验存在持续的非偏侧负性，F（1，11）= 7.13，p=。02，但在运动前的初始维持期内，F（1，11）= 1.46，p=. 25.这种负性显示双侧前部头皮分布，集中在额中央电极部位。这些结果表明，“额叶-中枢负性”作为一个候选的视觉工作记忆操作的神经生理标志，并建议存储和操作是独立的认知和神经机制。
Previous research has discovered the neural correlates of visual working memory storage capacity (eg, Vogel & Machizawa, 2004), but not the neural correlates of the defining feature of working memory–the manipulation of stored information. To this end, we recorded neural activity using electroencephalography (EEG) while observers completed a working memory (WM) manipulation task. Observers were cued to remember 3 colored circles on one side of the display (ignoring a perceptually matched display on the other side), followed by a maintenance period where the colors disappeared leaving behind placeholders. These events were succeeded by a placeholder-motion period, in which a pair of placeholders underwent smooth motion to swap locations. Observers were instructed to either update the spatial-featural bindings, keeping the features aligned with the moving placeholders (storage and manipulation) or to ignore the movement altogether and remember the features at their original locations (storage only). Observers subsequently identified the color of a cued item. We observed a sustained contralateral delay activity (CDA) at posterior electrode sites for both conditions during the initial maintenance prior to placeholder motion (representing the initial storage of information). This lateralized activity persevered into the placeholder-motion period, and remained active throughout this time window. The magnitude of the CDA did not differ between Update and Ignore conditions during either the initial maintenance period, F (1, 11)= 2.31, p=. 16, or the placeholder-motion period, F (1, 11)= 3.69, p=. 08. However, we observed a sustained nonlateralized negativity for Update trials, but not Ignore trials, at frontal-central electrode sites during the placeholder-motion period, F (1, 11)= 7.13, p=. 02, but not during the initial maintenance period before movement, F (1, 11)= 1.46, p=. 25. This negativity showed a bilateral anterior scalp distribution, focusing over frontal-central electrode sites. These results present the" Frontal-Central Negativity" as a candidate neurophysiological marker of visual WM manipulation, and suggest that storage and manipulation are separable cognitive and neural mechanisms.