Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary; Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary.
imec, Leuven, Belgium; Electrical Engineering Department (ESAT), KU Leuven, Leuven, Belgium.
J Neurosci Methods. 2019 Mar 15;316:58-70. doi: 10.1016/j.jneumeth.2018.08.020. Epub 2018 Aug 23.
The cortical slow (∼1 Hz) oscillation (SO), which is thought to play an active role in the consolidation of memories, is a brain rhythm characteristic of slow-wave sleep, with alternating periods of neuronal activity and silence. Although the laminar distribution of cortical activity during SO is well-studied by using linear neural probes, traditional devices have a relatively low (20-100 μm) spatial resolution along cortical layers.
In this work, we demonstrate a high-density linear silicon probe fabricated to record the SO with very high spatial resolution (∼6 μm), simultaneously from multiple cortical layers. Ketamine/xylazine-induced SO was acquired acutely from the neocortex of rats, followed by the examination of the high-resolution laminar structure of cortical activity.
The probe provided high-quality extracellular recordings, and the obtained cortical laminar profiles of the SO were in good agreement with the literature data. Furthermore, we could record the simultaneous activity of 30-50 cortical single units. Spiking activity of these neurons showed layer-specific differences.
The developed silicon probe measures neuronal activity with at least a three-fold higher spatial resolution compared with traditional linear probes. By exploiting this feature, we could determine the site of up-state initiation with a higher precision than before. Additionally, increased spatial resolution may provide more reliable spike sorting results, as well as a higher single unit yield.
The high spatial resolution provided by the electrodes allows to examine the fine structure of local population activity during sleep SO in greater detail.
皮质慢波（∼1Hz）振荡（SO）被认为在记忆巩固中起积极作用，是慢波睡眠中特征性的脑节律，具有神经元活动和沉默的交替周期。虽然线性神经探针对 SO 期间的皮质活动的层分布进行了很好的研究，但传统设备在皮质层之间的空间分辨率相对较低（20-100μm）。
在这项工作中，我们展示了一种高密度线性硅探针的制造，该探针具有非常高的空间分辨率（∼6μm），可同时从多个皮质层记录 SO。使用氯胺酮/甲苯噻嗪诱导的 SO 从大鼠新皮层中急性采集，然后检查皮质活动的高分辨率层结构。
探针提供了高质量的细胞外记录，并且获得的 SO 皮质层轮廓与文献数据非常吻合。此外，我们可以同时记录 30-50 个皮质单个单位的活动。这些神经元的放电活动表现出层特异性差异。
与传统的线性探针相比，开发的硅探针测量神经元活动的空间分辨率至少提高了三倍。利用这一特性，我们可以比以前更精确地确定上状态起始的位置。此外，增加的空间分辨率可能提供更可靠的尖峰分类结果，以及更高的单个单位产量。
电极提供的高空间分辨率允许更详细地检查睡眠 SO 期间局部群体活动的精细结构。
