Hakun Jonathan G, Ravizza Susan M
Department of Psychology, The Pennsylvania State University, University Park, PA, USA.
Department of Psychology, Michigan State University, East Lansing, MI 48824, USA.
Neuroimage. 2016 Jan 1;124(Pt A):783-793. doi: 10.1016/j.neuroimage.2015.09.056. Epub 2015 Oct 3.
The ability to maintain information in visual working memory (VWM) in the presence of ongoing visual input allows for flexible goal-directed behavior. Previous evidence suggests that categorical overlap between visual distractors and the contents of VWM is associated with both the degree to which distractors disrupt VWM performance and activation among fronto-parietal regions of cortex. While within-category distractors have been shown to elicit a greater response in ventral fronto-parietal regions, to date, no study has linked distractor-evoked response of these regions to VWM performance costs. Here we examined the contributions of ventral fronto-parietal cortex to the disruption of VWM storage by manipulating memoranda-distractor similarity. Our results revealed that the degree of activation across cortex was graded in a manner suggesting that similarity between the contents of VWM and visual distractors influenced distractor processing. While abrupt visual onsets failed to engage ventral fronto-parietal regions during VWM maintenance, objects sharing categorical- (Related objects) and feature-overlap (Matched objects) with VWM elicited a significant response in the right TPJ and right AI. Of central relevance, the magnitude of activation in the right AI elicited by both types of distractor objects subsequently predicted costs to binding change detection accuracy. In addition, Related and Matched distractors differentially affected ventral-dorsal connectivity between the right AI and dorsal parietal regions, uniquely contributing to disruption of VWM storage. Together, our current results implicate activation of ventral fronto-parietal cortex in disruption of VWM storage, and disconnection between ventral frontal and dorsal parietal cortices as a mechanism to protect the contents of VWM.
在持续的视觉输入存在的情况下,在视觉工作记忆(VWM)中保持信息的能力有助于灵活的目标导向行为。先前的证据表明,视觉干扰物与VWM内容之间的类别重叠既与干扰物破坏VWM表现的程度有关,也与皮质额顶叶区域的激活有关。虽然同类干扰物已被证明在腹侧额顶叶区域会引发更大的反应,但迄今为止,尚无研究将这些区域的干扰物诱发反应与VWM表现成本联系起来。在这里,我们通过操纵记忆-干扰物相似性来研究腹侧额顶叶皮质对VWM存储破坏的作用。我们的结果显示,整个皮质的激活程度呈梯度变化,这表明VWM内容与视觉干扰物之间的相似性影响了干扰物的处理。在VWM维持期间,突然的视觉刺激未能激活腹侧额顶叶区域,而与VWM共享类别(相关物体)和特征重叠(匹配物体)的物体在右侧颞顶联合区(TPJ)和右侧前岛叶(AI)引发了显著反应。至关重要的是,两种类型的干扰物物体在右侧AI引发的激活程度随后预测了绑定变化检测准确性的成本。此外,相关和匹配的干扰物对右侧AI与背侧顶叶区域之间的腹侧-背侧连接有不同影响,这独特地导致了VWM存储的破坏。总之,我们目前的结果表明腹侧额顶叶皮质的激活参与了VWM存储的破坏,并且腹侧额叶和背侧顶叶皮质之间的断开连接是保护VWM内容的一种机制。