The Bionic Ear Institute, East Melbourne 3002, Australia.
Epilepsy Res. 2010 May;89(2-3):261-70. doi: 10.1016/j.eplepsyres.2010.01.010. Epub 2010 Feb 13.
The aim of this study was to determine the current intensities necessary to elicit three levels of varying EEG and behavioural phenomena with electrical stimulation, and also to determine the consistency of the EEG and behavioural components of the triggered seizures over time. Electrical stimulation of the primary motor/somatosensory cortex was performed in 16 adult rats with multichannel microwire electrode arrays. Stimulation was delivered at a frequency of 60 Hz (1 ms pulse width), for 2 s duration, as biphasic rectangular pulses over four of the eight available electrode pairs. Current intensity thresholds for interruption of normal behaviour, epileptiform afterdischarge (EAD) longer than 5 s and motor seizures with Racine severity greater than 3 were not correlated to time post-surgery. The Racine threshold was shown to be negatively correlated to the EAD duration and Racine severity of seizures elicited in the following sessions. Seizures were reliably generated in rats through cortical stimulation with microwire electrode arrays and these seizures were not shown to be subject to any kindling type effects up to 53 days post-implantation. Both the electrographic duration and behavioural severity of stimulated seizures remained, on average, constant during this experimental period. Approximately one-third of stimulations did not cause observable motor seizures and of those that did result in seizures, forelimb clonus was the most common manifestation and the mean EAD duration was 18.5 s. No damage beyond that caused by surgical implantation of electrodes was observed in the histological analyses of stimulated and non-stimulated tissue. The consistency, duration and severity of seizures within this timeframe make this cortical stimulation model suitable for investigations into novel therapeutic interventions for epilepsy that require a known seizure focus.
本研究旨在确定通过电刺激引发三种不同程度脑电图和行为现象所需的电流强度，同时确定随着时间的推移触发癫痫发作的脑电图和行为成分的一致性。使用多通道微丝电极阵列对 16 只成年大鼠进行初级运动/体感皮层的电刺激。刺激以 60 Hz（1 ms 脉冲宽度）的频率，2 s 的持续时间，以双相矩形脉冲形式施加于八个可用电极对中的四个。中断正常行为、持续时间超过 5 s 的癫痫样后放电 (EAD) 和 Racine 严重程度大于 3 的运动性癫痫发作的电流强度阈值与手术后时间无关。Racine 阈值与随后各次诱发的 EAD 持续时间和癫痫发作的 Racine 严重程度呈负相关。通过微丝电极阵列对皮层进行刺激可靠地在大鼠中产生癫痫发作，这些癫痫发作在植入后 53 天内没有表现出任何 kindling 样效应。在这段实验期间，刺激性癫痫发作的脑电图持续时间和行为严重程度平均保持不变。大约三分之一的刺激不会引起可观察到的运动性癫痫发作，而那些导致癫痫发作的刺激中，前肢阵挛是最常见的表现，平均 EAD 持续时间为 18.5 s。在刺激和非刺激组织的组织学分析中，除了电极植入引起的损伤外，没有观察到其他损伤。在这个时间范围内，癫痫发作的一致性、持续时间和严重程度使得这种皮层刺激模型适合于研究需要已知癫痫灶的癫痫新治疗干预措施。
