Popken G J, Bunney W E, Potkin S G, Jones E G
Center for Neuroscience, University of California, Davis, CA 95616, USA.
Proc Natl Acad Sci U S A. 2000 Aug 1;97(16):9276-80. doi: 10.1073/pnas.150243397.
The hypoactivity of dorsolateral prefrontal cortex in schizophrenics is well known. One cause of this hypoactivity may be defective corticocortical or thalamocortical connections. Recent imaging studies of the thalamus suggest reductions in volume of the whole thalamus and reduced activity in the medial group of thalamic nuclei, which may indicate loss of functional input to the cortex. Using stereological techniques in six pairs of individually matched brains from schizophrenics and controls, we measured the volumes and obtained estimates of the number of neurons in the three subnuclei (parvocellular, pc; densocellular, dc; magnocellular, mc) of the mediodorsal nucleus (MD) and from the ventral posterior medial nucleus. There was a significant reduction in total neuron number in MD as a whole but this neuron loss was largely restricted to MDpc and MDdc [-30.9 and -24.5%, respectively (P </= 0.01)]. MDmc and the control ventral posterior medial nucleus showed no significant changes in cell number. Because the subnuclei of MD have different connections and project to different areas of the frontal cortex, the specific loss of neurons in MDpc and MDdc has implications for the functional defects observed in schizophrenia.
精神分裂症患者背外侧前额叶皮质活动减退是众所周知的。这种活动减退的一个原因可能是皮质-皮质或丘脑-皮质连接存在缺陷。最近对丘脑的影像学研究表明，整个丘脑体积减小，丘脑内侧核群活动降低，这可能表明皮质功能输入丧失。我们使用体视学技术，对来自精神分裂症患者和对照组的六对个体匹配的大脑进行研究，测量了体积，并估算了背内侧核（MD）三个亚核（小细胞部，pc；致密细胞部，dc；大细胞部，mc）以及腹后内侧核的神经元数量。MD整体的神经元总数显著减少，但这种神经元损失主要局限于MDpc和MDdc [分别减少30.9%和24.5%（P≤0.01）]。MDmc和对照腹后内侧核的细胞数量没有显著变化。由于MD的亚核具有不同的连接并投射到额叶皮质的不同区域，MDpc和MDdc中神经元的特异性损失对精神分裂症中观察到的功能缺陷具有重要意义。
