Brain Research Institute, Center for Cognitive Science, University of Bremen, Bremen, Germany.
J Neurophysiol. 2011 Jun;105(6):3092-105. doi: 10.1152/jn.00508.2010. Epub 2011 Mar 30.
In monkeys, long-term recordings with chronically implanted microelectrodes frequently suffer from a continuously decreasing probability to record single units or even small multiunit clusters. This problem is associated with two technical limitations of the available devices: first, restrictions for electrode movement, and second, absent possibility to exchange electrodes easily on a regular basis. Permitting to adjust the recording site and to use new recording tracks with proper electrodes may avoid these problems and make chronic more similar to acute recordings. Here, we describe a novel type of implant tackling this issue. It consists of a new type of recording chamber combined with an exchangeable multielectrode array that precisely fits into it. The multielectrode array is reversibly fixed to the chamber, and within a minute it can be exchanged against another array equipped with new electrodes at the awake animal. The array allows for bidirectional movement of six electrodes for a distance of up to 12 mm. The recording chamber enables hermetical isolation of the intracranial space, resulting in long-lasting aseptic conditions and reducing dural thickening to a minimum, as confirmed by microbiological and histopathological analysis. The device has a simple design and is both easy to produce and low in cost. Functionality has been tested in primary and secondary visual cortex of three macaque monkeys over a period of up to 15 mo. The results show that even after more than a year, single and multiunit responses can be obtained with high incidence.
在猴子中，使用长期植入的微电极进行的长期记录经常会遇到记录单个单元甚至小的多单元簇的可能性不断降低的问题。这个问题与可用设备的两个技术限制有关：首先，限制了电极的移动，其次，无法定期方便地更换电极。允许调整记录部位并使用带有适当电极的新记录轨道可能会避免这些问题，并使慢性更类似于急性记录。在这里，我们描述了一种新型的植入物，可解决此问题。它由一种新型的记录室和可交换的多电极阵列组成，该阵列可精确地安装在其中。多电极阵列可反向固定在腔室上，并且可以在一分钟内将其与另一配备有新电极的阵列在清醒动物身上进行交换。该阵列允许六个电极双向移动，距离可达 12 毫米。记录室可以实现颅内空间的密封隔离，从而在很长一段时间内保持无菌条件，并将硬脑膜增厚减少到最低限度，这已通过微生物学和组织病理学分析得到证实。该设备设计简单，易于生产且成本低廉。已在三只猕猴的初级和次级视觉皮层中对其功能进行了长达 15 个月的测试。结果表明，即使经过一年多，也可以以高发生率获得单个和多个单元的响应。
