Eytan Danny, Minerbi Amir, Ziv Noam, Marom Shimon
Dept. of Physiology and Biophysics, Faculty of Medicine, Technion, Haifa 31096, Israel.
J Neurophysiol. 2004 Sep;92(3):1817-24. doi: 10.1152/jn.00202.2004. Epub 2004 Apr 14.
The involvement of dopamine in the process of learning, at the cellular and behavioral levels, has been studied extensively. Evidently, dopamine is released from midbrain nuclei neurons on exposure to salient unpredicted stimuli and binds to neurons of cortical and subcortical structures, where its neuromodulatory effects are exerted. The neuromodulatory effects of dopamine at the synaptic and cellular levels are very rich, but it is difficult to extrapolate from these elementary levels what their effect might be at the behaviorally relevant level of neuronal ensembles. Using multi-site recordings from networks of cortical neurons developing ex vivo, we studied the effects of dopamine on connectivity within neuronal ensembles. We found that dopamine disperses correlations between individual neuronal activities while preserving the global distribution of correlations at the network level. Using selective D(1) and D(2) modulators, we show that both receptor types are contributing to dopamine-induced dispersion. Our results indicate that, at the neuronal ensemble level, dopamine acts to enhance changes in network connectivity rather than stabilize such connections.
多巴胺在细胞和行为水平上参与学习过程的研究已十分广泛。显然，在暴露于显著的意外刺激时，多巴胺从中脑核神经元释放，并与皮质和皮质下结构的神经元结合，在这些部位发挥其神经调节作用。多巴胺在突触和细胞水平上的神经调节作用非常丰富，但很难从这些基本水平推断其在行为相关的神经元集合水平上可能产生的影响。利用体外培养的皮质神经元网络进行多部位记录，我们研究了多巴胺对神经元集合内连接性的影响。我们发现，多巴胺分散了单个神经元活动之间的相关性，同时在网络水平上保留了相关性的全局分布。使用选择性D(1)和D(2)调节剂，我们表明这两种受体类型都促成了多巴胺诱导的分散。我们的结果表明，在神经元集合水平上，多巴胺的作用是增强网络连接性的变化，而不是稳定这种连接。
