Department of Psychology, Vanderbilt Vision Research Center, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, TN 37240, USA.
J Neurosci. 2012 May 30;32(22):7711-22. doi: 10.1523/JNEUROSCI.0215-12.2012.
Although areas of frontal cortex are thought to be critical for maintaining information in visuospatial working memory, the event-related potential (ERP) index of maintenance is found over posterior cortex in humans. In the present study, we reconcile these seemingly contradictory findings. Here, we show that macaque monkeys and humans exhibit the same posterior ERP signature of working memory maintenance that predicts the precision of the memory-based behavioral responses. In addition, we show that the specific pattern of rhythmic oscillations in the alpha band, recently demonstrated to underlie the human visual working memory ERP component, is also present in monkeys. Next, we concurrently recorded intracranial local field potentials from two prefrontal and another frontal cortical area to determine their contribution to the surface potential indexing maintenance. The local fields in the two prefrontal areas, but not the cortex immediately posterior, exhibited amplitude modulations, timing, and relationships to behavior indicating that they contribute to the generation of the surface ERP component measured from the distal posterior electrodes. Rhythmic neural activity in the theta and gamma bands during maintenance provided converging support for the engagement of the same brain regions. These findings demonstrate that nonhuman primates have homologous electrophysiological signatures of visuospatial working memory to those of humans and that a distributed neural network, including frontal areas, underlies the posterior ERP index of visuospatial working memory maintenance.
尽管额皮质区域被认为对维持视空间工作记忆中的信息至关重要，但在人类中，维持的事件相关电位 (ERP) 指标是在后皮质区域发现的。在本研究中，我们调和了这些看似矛盾的发现。在这里，我们表明，猕猴和人类表现出相同的工作记忆维持的后 ERP 特征，该特征预测了基于记忆的行为反应的精度。此外，我们还表明，最近证明是人类视觉工作记忆 ERP 成分基础的 alpha 波段中的节律性振荡的特定模式也存在于猴子中。接下来，我们同时从两个前额皮质和另一个额皮质区域记录颅内局部场电位，以确定它们对表面电位索引维持的贡献。两个前额皮质区域中的局部场，而不是紧邻的后皮质区域，表现出幅度调制、时间和与行为的关系，表明它们有助于从远端后皮质电极测量的表面 ERP 成分的产生。维持过程中的 theta 和 gamma 波段的节律性神经活动为相同脑区的参与提供了有力的支持。这些发现表明，非人类灵长类动物具有与人类相同的视空间工作记忆的同源电生理特征，并且包括额皮质区域在内的分布式神经网络是视空间工作记忆维持的后 ERP 指标的基础。
