Sreenivasan Kartik K, Gratton Caterina, Vytlacil Jason, D'Esposito Mark
Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA,
Cogn Affect Behav Neurosci. 2014 Mar;14(1):117-28. doi: 10.3758/s13415-013-0246-7.
Isolating the short-term storage component of working memory (WM) from the myriad of associated executive processes has been an enduring challenge. Recent efforts have identified patterns of activity in visual regions that contain information about items being held in WM. However, it remains unclear (1) whether these representations withstand intervening sensory input and (2) how communication between multimodal association cortex and the unimodal perceptual regions supporting WM representations is involved in WM storage. We present evidence that the features of a face held in WM are stored within face-processing regions, that these representations persist across subsequent sensory input, and that information about the match between sensory input and a memory representation is relayed forward from perceptual to prefrontal regions. Participants were presented with a series of probe faces and indicated whether each probe matched a target face held in WM. We parametrically varied the feature similarity between the probe and target faces. Activity within face-processing regions scaled linearly with the degree of feature similarity between the probe face and the features of the target face, suggesting that the features of the target face were stored in these regions. Furthermore, directed connectivity measures revealed that the direction of information flow that was optimal for performance was from sensory regions that stored the features of the target face to dorsal prefrontal regions, supporting the notion that sensory input is compared to representations stored within perceptual regions and is subsequently relayed forward. Together, these findings indicate that WM storage operations are carried out within perceptual cortex.
将工作记忆（WM）的短期存储成分与众多相关的执行过程分离，一直是一项持久的挑战。最近的研究努力已经确定了视觉区域中的活动模式，这些模式包含了WM中所保存项目的信息。然而，仍不清楚：（1）这些表征能否经受住中间的感觉输入；（2）多模态联合皮层与支持WM表征的单模态感知区域之间的通信如何参与WM存储。我们提供的证据表明，WM中保存的面部特征存储在面部处理区域内，这些表征在随后的感觉输入中持续存在，并且关于感觉输入与记忆表征之间匹配的信息从感知区域向前传递到前额叶区域。向参与者呈现一系列探测面部，并指示每个探测面部是否与WM中保存的目标面部匹配。我们对探测面部与目标面部之间的特征相似度进行了参数化变化。面部处理区域内的活动与探测面部和目标面部特征之间的特征相似度呈线性比例变化，这表明目标面部的特征存储在这些区域。此外，定向连接性测量显示，对表现最有利的信息流方向是从存储目标面部特征的感觉区域到背侧前额叶区域，这支持了将感觉输入与存储在感知区域内的表征进行比较并随后向前传递的观点。总之，这些发现表明WM存储操作是在感知皮层内进行的。
