目的:用逆行标记方法观察脑干神经元向皮质扣带回中部(the middle portion of the cingulate cortex,MCC)的纤维投射。方法:立体定位注射法将0.06-0.08μl的4%荧光金(Fluoro-gold,FG)注射至MCC(Bregmma:+0.2,-0.3,-0.8 mm)部位,7 d后处死大鼠,含4%多聚甲醛的磷酸缓冲液(PB)灌注固定,取脑组织,制作30μm厚度的冰冻切片,荧光显微镜下观察FG逆行标记神经元的定位分布并计数。结果:MCC与皮质间有广泛的联系,包括与同侧、对侧和扣带回内部的联系。在脑干中缝核簇、蓝斑、被盖腹侧区、被盖背内侧区及中脑中央灰质(α部)均可观察到FG逆标神经元的分布,以上FG标记神经元以同侧为主,对侧较少。结论:以上核团向MCC的投射表明MCC接受来自脑干神经元的广泛投射,提示MCC神经元的活动受到脑干众多结构的调控。
Objective:The afferents from brain stem to the middle portion of the cingulate cortex( MCC) in the present study were investigated by using retrograde tracing technique.Methods:A volume of 0.06 - 0.08 μl 4% Fluoro-gold( FG) was injected into MCC( Bregmma:+ 0.2,-0.3,-0.8 mm) by using a stereotaxic apparatus.The rats were euthanized,perfused with 4% paraformaldehyde in phosphate buffer( PB) at the 7th days after injection.Rat brains were sectioned in the coronal planes at 30 μm.FG retrogradely labeled neurons were examined using fluorescence microscope.Results:The present results have demonstrated that there were extensive MCC-cortical connections,including ipsilateral,contralateral and intracingulate connectivity.The distribution of FG-labeled neurons in the brain stem including raphe nuclei,locus coeruleus,ventral tegmental area,dorsomedial tegmental area and midbrain central gray( alpha part) were frequently observed.These FG-labeled neurons were mainly ipsilateral dominance and less in contralateral.Conclusion:The topographic afferents to the MCC indicates that MCC receives widespread projections from brainstem,suggesting that neuronal activities in the MCC are extensively modulated by diverse brain stem structures.