丘脑腹外侧核团细胞电活动与原发性震颤

Neuronal activity of ventrolateral thalamus in patients with essential tremor

目的探讨与原发性震颤（ET）相关的丘脑腹外侧核（Vop和Vim）细胞电活动。方法以10例ET患者和10例原发性帕金森病（PD）患者为研究对象，在实施立体定向手术的同时采集Vop／Vim细胞电活动和肢体EMG。用单细胞和峰间隔（ISI）分析不同细胞放电模式和频率。结果发现266个神经元，包括与震颤相关的细胞放电活动（101个），紧张性放电活动（85个）和不规则放电活动（80个）。在10个ET患者针道中发现131个神经元，除29．0％与震颤相关的细胞放电活动外，41．2％为紧张性放电活动，平均细胞自发放电频率（MSFR）为（55±21）Hz；29．8％为不规则放电活动，MSFR为（32±17）Hz。在PD患者10个针道中发现135个神经元，除46．7％与震颤相关的放电活动外，23．0％为紧张性放电活动，MSFR为（39±15）Hz；30．3％为不规则放电活动，MSFR为（21±8）Hz。进一步分析发现ET的紧张性和不规则放电活动的MSFR明显高于PD（t分别为2．74，2．72，均P〈0．05）。另外发现ET的Vop和Vim的MSFR分别为31．4Hz和59．0Hz，显著高于PD的Vop和Vim 16．8Hz和34．5Hz（t分别为4．43，4．92，均P〈0．05）。结论Vim接受来自小脑的投射，Vim神经元放电频率的增加提示ET的病理生理可能与小脑的过度活跃相关。

Objective To investigate the neuronal activity in the ventrolateral thalamus in relation to essential tremor （ET）. Methods Microelectrode recording in the ventral oral posterior （Vop） and ventral intermediate nucleus （Vim） of thalamus was performed on 10 patients with ET and 10 patients with Parkinson＇s disease （PD） who underwent thalamotomy for tremor during operation. Electromyography （EMG） was carried out on the eontralateral limbs simultaneously. Single unit analysis was performed to measure the interspike interval （ISI） and histogram was constructed to evaluate the pattern of neuronal activity. Student t-test was employed to compare the mean spontaneous firing rate （MSFR） and ISI of neuronal firing in Vop/Vim between the ET patients and PD patients, and correlation test Results Two hundred and sixty-six neurons were identified from 20 trajectories, 38.0% being neurons with tremor-related neuronal activity Tremor cells, 31.9% of neurons related to tonic firing, and 30.1% of neurons related to irregular discharge. 131 of these thalamic neurons, were obtained from 10 ET patients. 38 of these 131 neurons （29.0%） were related to tremor-related neuronal activity, 54 （41.2%） neurons were related to tonic firing with a mean spontaneous firing rate （MSFR） of （55 ±21 ） Hz, and 39 neurons （29.8%） were related to irregular discharge with a MSFR of （32 ± 17） Hz. In the meantime, 135 neurons were obtained from 10 PD patients . Of these 135 neurons 63 （46.7%） were related to tremor, 31 neurons （23.0%） related to tonic firing with a MSFR of （39 ± 15） Hz, and 41 （30.3%） were related to irregular discharge with a MSFR of（21 ± 8 ）Hz. The MSFR levels of pooled neurons in Vop/Vim with tonic firing and irregular discharge of the ET patients were significantly higher than those of the PD patents （t = 2.74 and 2.99, both P 〈 0.05 ）. And the MSFR levels in Vop and Vim of the ET patients were significantly higher than those of the PD patients （both P 〈 0.05 ）. Conclusion Vim receives the projection from cerebellum. The increase of neuronal firing frequency observed in Vim suggests that the pathophysiology of ET may be correlated with excessive activity of cerebellum.