Zhang Yunfeng, Hamilton Susan E, Nathanson Neil M, Yan Jun
Department of Physiology, Hotchkiss Brain Institute, University of Calgary Faculty of Medicine, Calgary, Alberta T2N 4N1, Canada.
Cereb Cortex. 2006 Sep;16(9):1258-65. doi: 10.1093/cercor/bhj067. Epub 2005 Nov 16.
Muscarinic acetylcholine receptors are extensively involved in cortical cognition and learning-induced or experience-dependent cortical plasticity. The most abundant muscarinic receptor subtype in the cerebral cortex is the M1 receptor, but little is known about its contribution to experience-dependent plasticity of the adult auditory cortex. We have examined the role of the M1 receptor in experience-dependent plasticity of the auditory cortex in mice lacking the M1 (chrm1) gene. We show here that electrical stimulation of the basal forebrain, a major source of cortical cholinergic inputs, facilitated the auditory responses of cortical neurons in both wild types and M1 mutants. The basal forebrain stimulation alone caused change in the best frequencies of cortical neurons that were significantly greater in M1 mutants. When animals received the paired stimuli of electrical stimulation of the basal forebrain and tone, the frequency tuning of cortical neurons systematically shifted toward the frequency of the paired tone in both wild types and M1 mutants. However, the shift range in M1 mutants was much smaller than that in wild-type mice. Our data suggest that the M1 receptor is important for the experience-dependent plasticity of the auditory cortex.
毒蕈碱型乙酰胆碱受体广泛参与皮层认知以及学习诱导或经验依赖的皮层可塑性。大脑皮层中最丰富的毒蕈碱受体亚型是M1受体，但关于其对成年听觉皮层经验依赖可塑性的贡献却知之甚少。我们研究了M1受体在缺乏M1（chrm1）基因的小鼠听觉皮层经验依赖可塑性中的作用。我们在此表明，对基底前脑（皮层胆碱能输入的主要来源）进行电刺激，可促进野生型和M1突变体小鼠皮层神经元的听觉反应。单独的基底前脑刺激导致皮层神经元最佳频率的变化，在M1突变体中这种变化显著更大。当动物接受基底前脑电刺激与纯音的配对刺激时，野生型和M1突变体小鼠皮层神经元的频率调谐均系统地向配对纯音的频率偏移。然而，M1突变体中的偏移范围比野生型小鼠小得多。我们的数据表明，M1受体对听觉皮层的经验依赖可塑性很重要。
