Jiménez F, Velasco F, Velasco M, Brito F, Morel C, Márquez I, Pérez M L
Unidad de Neurocirugía Estereotáctica y Funcional, Hospital General de México, México, D.F., Mexico.
Arch Med Res. 2000 May-Jun;31(3):270-81. doi: 10.1016/s0188-4409(00)00066-7.
Previous reports have provided evidence of a reticulo-thalamic system, extending from the mesencephalic reticular formation (MRF) to the ventrolateral thalamus (VL), involved in the production of tremor. In humans, a funnel of fibers in the posterior subthalamus named the prelemniscal radiations (Raprl) has been described as an exquisite target to treat tremor in cases of Parkinson's disease. In the present study, a group of 14 patients suffering from Parkinson's disease, with prominent unilateral tremor and rigidity, were implanted with tetrapolar depth brain stimulation (DBS) electrodes in Raprl to perform chronic electrical stimulation (ES) for the treatment of patient symptoms. Electrodes were left externalized to corroborate their placement throughout MRI studies and also to perform the following electrophysiological battery: (a) recording of somatosensory-evoked responses (SEP) through different electrode contacts and scalp by means of a paradigm to study the attention process; (b) evoking scalp EEG responses by stimulation with low (3 cps, 6 cps) and high (60-120 cps) frequencies with stimuli delivered through different electrode contacts, and (c) studying recovery cycle (RC) potentials in the Raprl while the upper MRF was being stimulated and, conversely, the RC in MRF while Raprl was being stimulated, before and after subacute Raprl stimulation. Thereafter, the electrodes were internalized and connected to a pulse generator (IPG) to carry on chronic ES, while the effects of stimulation were determined through a quantitative evaluation that measured phasic and tonic muscular activity with EMG recordings during different motor tasks. Results indicate the following: (a) that late, but not early, SEP components were recorded in Raprl and modulated in different attentive conditions; (b) that bilateral recruiting responses and spike and wave complexes were elicited by Raprl through low-frequency stimulation, while bilateral positive DC shifts induced by high-frequency stimulation were recorded, similar to those obtained in animals from MRF, and (c) that Raprl-ES induced RC inhibition at Raprl, but Raprl ES did not change MRF-RC. Long-term Raprl-ES induced a significant decrease in tremor and rigidity. It was concluded that Raprl represents a subthalamic circuit electrophysiologically related to MRF in the genesis of tremor and rigidity and in the process of selective attention. Raprl-ES induced a significant improvement in tremor and rigidity by causing inhibition of the stimulated area.
先前的报告已提供证据表明，存在一个从中脑网状结构（MRF）延伸至丘脑腹外侧（VL）的网状丘脑系统，该系统参与震颤的产生。在人类中，丘脑底后部一束被称为丘脑前辐射（Raprl）的纤维束，已被描述为治疗帕金森病患者震颤的一个精准靶点。在本研究中，一组14例患有帕金森病、伴有明显单侧震颤和强直的患者，在Raprl植入四极深度脑刺激（DBS）电极，以进行慢性电刺激（ES）来治疗患者症状。电极保持体外放置，以便在整个MRI研究过程中确认其位置，同时进行以下电生理检查：（a）通过不同电极触点和头皮记录体感诱发电位（SEP），采用一种范式来研究注意力过程；（b）通过不同电极触点施加低频率（3 cps、6 cps）和高频率（60 - 120 cps）刺激诱发头皮脑电图反应，以及（c）在亚急性Raprl刺激前后，刺激上MRF时研究Raprl中的恢复周期（RC）电位，反之，刺激Raprl时研究MRF中的RC电位。此后，将电极植入体内并连接到脉冲发生器（IPG）以进行慢性ES，同时通过定量评估来确定刺激效果，该评估通过在不同运动任务期间用肌电图记录测量相位和紧张性肌肉活动。结果表明：（a）在Raprl中记录到了晚期而非早期的SEP成分，并且在不同的注意力条件下受到调制；（b）Raprl通过低频刺激诱发双侧募集反应以及棘波和慢波复合波，同时记录到高频刺激诱发的双侧正向直流偏移，这与在动物中从MRF获得的结果相似，以及（c）Raprl - ES在Raprl处诱导RC抑制，但Raprl - ES并未改变MRF - RC。长期的Raprl - ES导致震颤和强直显著减轻。得出的结论是，在震颤和强直的发生以及选择性注意力过程中，Raprl代表了一个在电生理上与MRF相关的丘脑底核电路。Raprl - ES通过抑制受刺激区域，使震颤和强直得到显著改善。
