Objective To explore the firing activity of the ventromedial thalamic nucleus（VM）in rats with unilateral 6⁃OHDA lesions. Methods The recording electrodes were implanted in the bilateral ventromedial thalamic nucleus of SD rats via stereotactic surgery，and the stainless steel cannula for 6⁃OHDA injection was implanted above the right medial forebrain bundle. The unilateral Parkinson′s disease rat model was induced by injection of 12 μg/4 μL 6⁃OHDA into the right medial forebrain bundle. Extracellular signals in the bilateral VM were recorded in vivo using multi⁃channel methods before and after lesion. Tyrosine hydroxylase immunohistochemical staining was used to detect the damage of dopaminergic neurons in substantianigra. Cresol violet staining was used to determine the positions of the tips of the recording electrodes. Results In model rats，the mean firing rates of neurons in the left VM and the right VM were（15.528 7 ± 0.572 69）Hz and（5.698 1 ± 0.279 1）Hz，respectively，with significant difference（t = 15.431，P < 0.001）. Compared with that before the establishment of the model，the mean firing rates of neurons in the right VM decreased significantly after the establishment of the model （F = 306.701，P < 0.001）. Before and after the model′s establishment，the rates of burst firing neurons in the right VM were 14.8 % and 44.4 %，respectively. Compared with that before the establishment of the model，the proportion of burst firing neurons in the right VM was significantly higher after the establishment of the model（P = 0.001）. Compared with that in the left VM，the proportion of burst firing neurons in the right VM increased significantly in the model rats and the difference was statistically significant（χ2 = 8.355，P = 0.004）. Conclusion In rats with unilateral 6⁃OHDA lesions，the firing activity of the ventromedial thalamic nucleus changed significantly. The ventromedial thalamic nucleus may be important in the pathophysiology of Parkinson′s disease.

目的 研究6-羟基多巴胺（6-OHDA）单侧帕金森病模型大鼠的丘脑腹内侧核神经元的放电活动。方法 使用大鼠脑立体定位仪把记录电极尖端置入SD大鼠双侧的丘脑腹内侧核，把用于后期注射6-OHDA的不锈钢管一端置入右侧内侧前脑束的上方。向右侧内侧前脑束内注入12μg/4μL的6-OHDA制作单侧帕金森病大鼠模型。采用神经元单位放电在体多通道同步记录方法记录模型建立前和模型建立后的双侧丘脑腹内侧核神经元的动作电位。应用酪氨酸羟化酶免疫组织化学染色观察黑质内多巴胺能神经元的丧失情况。应用甲酚紫染色对记录电极尖端进行定位。结果 模型大鼠的左侧和右侧丘脑腹内侧核神经元的平均放电频率分别是（15.528 7±0.572 69）Hz和（5.698 1±0.279 1）Hz，两者的差异有统计学意义（t=15.431,P

海南省高等学校科学研究项目（编号：Hnky-2021-38）;; 海南省卫生计生行业科研项目（编号：20A200319）;; 海南省自然科学基金高层次人才项目（编号：821RC698）