Bionics Institute, East Melbourne, Australia. Author to whom any correspondence should be addressed.
J Neural Eng. 2020 Mar 26;17(2):026008. doi: 10.1088/1741-2552/ab7a51.
The efficacy of deep brain stimulation can be limited by factors including poor selectivity of stimulation, targeting error, and complications related to implant reliability and stability. We aimed to improve surgical outcomes by evaluating electrode leads with smaller diameter electrode and microelectrodes incorporated which can be used for assisting targeting.
Electrode arrays were constructed with two different diameters of 0.65 mm and the standard 1.3 mm. Micro-electrodes were incorporated into the slim electrode arrays for recording spiking neural activity. Arrays were bilaterally implanted into the medial geniculate body (MGB) in nine anaesthetised cats for 24-40 h using stereotactic techniques. Recordings of auditory evoked field potentials and multi-unit activity were obtained at 1 mm intervals along the electrode insertion track. Insertion trauma was evaluated histologically.
Evoked auditory field potentials were recorded from ring and micro-electrodes in the vicinity of the medial geniculate body. Spiking activity was recorded from 81% of the microelectrodes approaching the MGB. Histological examination showed localized surgical trauma along the implant. The extent of haemorrhage surrounding the track was measured and found to be significantly reduced with the slim electrodes (541 ± 455 µm vs. 827 ± 647 µm; P < 0.001). Scoring of the trauma, focusing on tissue disruption, haemorrhage, oedema of glial parenchyma and pyknosis, revealed a significantly lower trauma score for the slim electrodes (P < 0.0001).
The slim electrodes reduced the extent of acute trauma, while still providing adequate electrode impedance for both stimulating and recording, and providing the option to target stimulate smaller volumes of tissue. The incorporation of microelectrodes into the electrode array may allow for a simplified, single-step surgical approach where confirmatory micro-targeting is done with the same lead used for permanent implantation.
深部脑刺激的疗效可能受到刺激选择性差、靶向误差以及与植入物可靠性和稳定性相关的并发症等因素的限制。我们旨在通过评估具有较小直径电极和微电极的电极引线来改善手术结果，这些电极可用于辅助靶向。
构建了两种不同直径的 0.65 毫米和标准的 1.3 毫米的电极阵列。将微电极纳入到细长的电极阵列中，用于记录尖峰神经活动。使用立体定向技术将电极阵列双侧植入麻醉猫的内侧膝状体（MGB）24-40 小时。在电极插入轨迹的 1 毫米间隔处获得听觉诱发电场电位和多单位活动的记录。使用组织学方法评估插入性创伤。
在靠近内侧膝状体的环形和微电极附近记录到听觉诱发电场电位。在接近 MGB 的微电极中，有 81%记录到尖峰活动。组织学检查显示植入物周围存在局部手术性创伤。测量了围绕轨迹的出血程度，发现细长电极的出血程度明显降低（541±455 µm 比 827±647 µm；P<0.001）。对损伤的评分侧重于组织破坏、出血、胶质实质水肿和固缩，发现细长电极的损伤评分明显降低（P<0.0001）。
细长电极减少了急性创伤的程度，同时仍然为刺激和记录提供了足够的电极阻抗，并提供了刺激更小体积组织的选择。将微电极纳入电极阵列中可能允许采用简化的、单步手术方法，其中使用用于永久性植入的相同引线进行确认性微靶向。
