Faculty of Psychology, Swiss Distance University Institute, Brig, Switzerland.
Institute of Psychology, University of Lausanne, Lausanne, Switzerland.
Eur J Neurosci. 2024 Aug;60(4):4421-4436. doi: 10.1111/ejn.16446. Epub 2024 Jun 11.
Several brain regions in the frontal, occipital and medial temporal lobes are known to contribute to spatial information processing. In contrast, the oscillatory patterns contributing to allocentric spatial working memory maintenance are poorly understood, especially in humans. Here, we tested twenty-three 21- to 32-year-old and twenty-two 64- to 76-year-old healthy right-handed adults in a real-world, spatial working memory task and recorded electroencephalographic (EEG) activity during the maintenance period. We established criteria for designating recall trials as perfect (no errors) or failed (errors and random search) and identified 8 young and 13 older adults who had at least 1 perfect and 1 failed trial amongst 10 recall trials. Individual alpha frequency-based analyses were used to identify oscillatory patterns during the maintenance period of perfect and failed trials. Spectral scalp topographies showed that individual theta frequency band relative power was stronger in perfect than in failed trials in the frontal midline and posterior regions. Similarly, gamma band (30-40 Hz) relative power was stronger in perfect than in failed trials over the right motor cortex. Exact low-resolution brain electromagnetic tomography in the frequency domain identified greater theta power in perfect than in failed trials in the secondary visual area (BA19) and greater gamma power in perfect than in failed trials in the right supplementary motor area. The findings of this exploratory study suggest that theta oscillations in the occipital lobe and gamma oscillations in the secondary motor cortex (BA6) play a particular role in successful allocentric spatial working memory maintenance.
已知额叶、枕叶和内侧颞叶的几个脑区有助于空间信息处理。相比之下，对于参与非定域空间工作记忆维持的振荡模式，人们知之甚少，尤其是在人类中。在这里，我们在现实世界的空间工作记忆任务中测试了 23 名 21 至 32 岁和 22 名 64 至 76 岁的健康右利手成年人，并在维持期记录了脑电图（EEG）活动。我们为指定回忆试验为完美（无错误）或失败（错误和随机搜索）制定了标准，并确定了 8 名年轻和 13 名年龄较大的成年人，他们在 10 次回忆试验中至少有 1 次完美和 1 次失败试验。基于个体阿尔法频率的分析用于识别完美和失败试验维持期的振荡模式。频谱头皮地形图显示，在额叶中线和后区，个体 theta 频带相对功率在完美试验中强于失败试验。同样，在右运动皮层上，伽马频带（30-40 Hz）的相对功率在完美试验中强于失败试验。在频域中进行的精确低分辨率脑电磁断层扫描确定，在次要视觉区（BA19）中，完美试验的 theta 功率大于失败试验，在右辅助运动区中，完美试验的伽马功率大于失败试验。这项探索性研究的结果表明，枕叶中的 theta 振荡和次级运动皮层（BA6）中的 gamma 振荡在成功的非定域空间工作记忆维持中发挥了特殊作用。
