Scott Nicole M, Leuthold Arthur, Sera Maria D, Georgopoulos Apostolos P
Center for Cognitive Sciences, University of Minnesota, Minneapolis, MN, USA.
Department of Neuroscience, University of Minnesota, 321 Church Street, Minneapolis, MN, 55455, USA.
Exp Brain Res. 2016 Feb;234(2):429-41. doi: 10.1007/s00221-015-4467-6. Epub 2015 Oct 29.
Children learn the words for above-below relations earlier than for left-right relations, despite treating these equally well in a simple visual categorization task. Even as adults--conflicts in congruency, such as when a stimulus is depicted in a spatially incongruent manner with respect to salient global cues--can be challenging. Here we investigated the neural correlates of encoding and maintaining in working memory above-below and left-right relational planes in 12 adults using magnetoencephalography in order to discover whether above-below relations are represented by the brain differently than left-right relations. Adults performed perfectly on the task behaviorally, so any differences in neural activity were attributed to the stimuli's cognitive attributes. In comparing above-below to left-right relations during stimulus encoding, we found the greatest differences in neural activity in areas associated with space and movement. In comparing congruent to incongruent trials, we found the greatest differential activity in premotor areas. For both contrasts, brain areas involved in the encoding phase were also involved in the maintenance phase, which provides evidence that those brain areas are particularly important in representing the relational planes or congruency types throughout the trial. When comparing neural activity associated with the relational planes during working memory, additional right posterior areas were implicated, whereas the congruent-incongruent contrast implicated additional bilateral frontal and temporal areas. These findings are consistent with the hypothesis left-right relations are represented differently than above-below relations.
儿童学习表示上下关系的词汇比学习左右关系的词汇要早，尽管在简单的视觉分类任务中他们对这两种关系的处理同样出色。即使是成年人，在一致性方面也会出现冲突，比如当一个刺激相对于显著的全局线索以空间上不一致的方式呈现时，这可能具有挑战性。在这里，我们使用脑磁图对12名成年人在工作记忆中编码和维持上下和左右关系平面的神经关联进行了研究，以发现大脑对上下关系的表征是否与左右关系不同。成年人在任务中的行为表现完美，因此神经活动的任何差异都归因于刺激的认知属性。在刺激编码过程中比较上下关系和左右关系时，我们发现在与空间和运动相关的区域神经活动差异最大。在比较一致试验和不一致试验时，我们在前运动区发现了最大的差异活动。对于这两种对比，编码阶段涉及的脑区在维持阶段也有参与，这表明这些脑区在整个试验过程中对表征关系平面或一致性类型特别重要。在工作记忆期间比较与关系平面相关的神经活动时，额外的右后区域被牵连，而一致 - 不一致对比则牵连额外的双侧额叶和颞叶区域。这些发现与左右关系的表征与上下关系不同的假设一致。
