丘脑背内侧核损毁对大鼠内侧前额叶皮层神经元电活动的影响

Effects of mediodorsal thalamic nucleus lesions on neuronal activity in medial prefrontal cortex of rats

目的探讨丘脑背内侧核(MD)损毁对大鼠内侧前额叶皮层(mPFC)中神经元电活动的影响。方法实验大鼠随机分成正常组(n=15)和MD损毁组(n=15),MD损毁后2周,采用在体细胞外生物电记录的方法,观察mPFC中锥体神经元以及中间神经元的放电频率、变异系数以及放电形式的变化。结果与正常组大鼠相比,损毁MD后,大鼠mPFC中锥体神经元的放电频率较正常组显著增加,且差异具有统计学意义(P<0.001),放电形式更趋于爆发式活动;而mPFC中间神经元的放电频率在MD损毁后明显降低,与正常组相比差异有统计学意义(P<0.05),且放电形式趋向于不规则。结论 MD损毁对大鼠mPFC锥体及中间神经元的电活动均有显著影响,表明MD对mPFC的功能活动可能起到重要的调节作用。

Objective To investigate the activity of medial prefrontal cortex（ m PFC） pyramidal neurons and interneurons in normal and mediodorsal thalamic nucleus（ MD）-damaged rats. Methods The experiments were performed in normal rats（ n = 15） and rats with MD lesions（ n = 15）,The change of the spontaneous firing of neurons in m PFC was observed after unilateral lesions of the MD by extracellular recording in vivo. Results Compared with normal rats,the firing rate of m PFC pyramidal neurons was significantly increased in rats with MD lesion（ P〈0. 001）,and the firing pattern changed towards a more burst-firing. Compared with normal rats,the firing rate of interneurons was markedly decreased in rats with MD lesion（ P〈0. 05）,and the firing pattern tended to irregular-firing activities. Conclusion These results suggest that neuronal activity of the m PFC is modulated by the MD,which may be very important for the regulation of m PFC function.