Department of Anesthesiology, Rush University Medical Center, Chicago, Illinois 60612, USA.
J Neurosurg. 2012 May;116(5):1134-43. doi: 10.3171/2011.12.JNS102176. Epub 2012 Feb 17.
Insight may be gained into the physiological mechanisms of deep brain stimulation (DBS) by analyzing local and contralateral subthalamic nucleus (STN) single-unit activity during activation of previously placed DBS electrodes. Special techniques are required to perform such analysis due to the presence of a large stimulus artifact. The purpose of this study was to determine the effects of DBS stimulation on single unit activity acquired from patients undergoing new or revised DBS placements.
Subthalamic nucleus single unit activity was acquired from awake patients during activation of a previously implanted STN DBS electrode. Stimulation was contralateral to the recording site in 4 cases and ipsilateral in 3. Data were acquired at stimulation frequencies of 30, 60, and 130 Hz and with other stimulation parameters at clinically effective settings. Cells were included if they showed kinesthetic activity before and after the stimulation paradigm and if their action potential morphology was maintained throughout the experiment. Analysis of single-unit activity acquired before, during, and after stimulation was performed employing a time-domain algorithm to overcome the stimulus artifact.
Both ipsilateral and contralateral acute stimulation resulted in reversible STN firing rate suppression. The degree of suppression became greater as stimulus frequency increased and was significant at 60 Hz (t-test, p < 0.05) and 130 Hz (p < 0.01). Suppression with ipsilateral 130-Hz stimulation ranged between 52.8% and 99.8%, whereas with similar contralateral STN stimulation, the range was lower (1.9%-50.3%). Return to baseline activity levels typically occurred within seconds after stimulation ended.
Stimulation of the STN at clinically effective frequencies has an acute suppressive rather than an excitatory effect on STN single-unit activity. The effect is bilateral, even though the degree of suppression is greater on the ipsilateral than the contralateral STN. The authors' algorithm helps reveal this effect in human patients.
通过分析先前放置的 DBS 电极激活期间同侧和对侧丘脑底核（STN）单个核团活动，深入了解深部脑刺激（DBS）的生理机制。由于存在较大的刺激伪影，因此需要特殊技术来进行此类分析。本研究旨在确定 DBS 刺激对接受新或修订 DBS 放置的患者采集的单个核团活动的影响。
在激活先前植入的 STN DBS 电极期间，从清醒患者中采集 STN 单个核团活动。在 4 例中，刺激位于记录部位的对侧，在 3 例中位于同侧。在 30、60 和 130 Hz 的刺激频率以及其他临床有效的刺激参数下采集数据。如果细胞在刺激范式前后显示运动觉活动，并且整个实验过程中其动作电位形态保持不变，则将其纳入研究。使用时域算法对刺激前后采集的单个核团活动进行分析，以克服刺激伪影。
同侧和对侧急性刺激均导致 STN 放电率可逆抑制。随着刺激频率的增加，抑制程度增大，在 60 Hz（t 检验，p <0.05）和 130 Hz（p <0.01）时具有统计学意义。同侧 130-Hz 刺激的抑制范围为 52.8%至 99.8%，而类似的对侧 STN 刺激的抑制范围较低（1.9%至 50.3%）。刺激结束后，通常在几秒钟内恢复到基线活动水平。
在临床有效频率下刺激 STN 对 STN 单个核团活动具有急性抑制作用，而不是兴奋作用。该效应是双侧的，尽管同侧 STN 的抑制程度大于对侧。作者的算法有助于在人类患者中揭示这种效应。
