Nicola Saleem M, Hopf F Woodward, Hjelmstad Gregory O
Ernest Gallo Clinic and Research Center, University of California, San Francisco, 5858 Horton St., Ste. 200, Emeryville, CA 94608, USA.
Cell Tissue Res. 2004 Oct;318(1):93-106. doi: 10.1007/s00441-004-0929-z. Epub 2004 Jul 28.
Dopamine functions as an important neuromodulator in the dorsal striatum and ventral striatum/nucleus accumbens. Evidence is accumulating for the idea that striatal neurons compete with each other for control over the animal's motor resources, and that dopamine plays an important modulatory role that allows a particular subset of neurons, encoding a specific behavior, to predominate in this competition. One means by which dopamine could facilitate selection among competing neurons is to enhance the contrast between stronger and weaker excitations (or to increase the "signal to noise ratio" among neurons, where the firing of the most excited neurons is assumed to transmit signal and the firing of the least excited to transmit noise). Here, we review the electrophysiological evidence for this hypothesis and discuss potential cellular mechanisms by which dopamine-mediated contrast enhancement could occur.
多巴胺在背侧纹状体和腹侧纹状体/伏隔核中作为一种重要的神经调质发挥作用。越来越多的证据支持这样一种观点，即纹状体神经元相互竞争以控制动物的运动资源，并且多巴胺发挥着重要的调节作用，使编码特定行为的特定神经元子集在这种竞争中占主导地位。多巴胺促进竞争神经元之间选择的一种方式是增强较强和较弱兴奋之间的对比度（或者增加神经元之间的“信噪比”，其中假设最兴奋神经元的放电传递信号，最不兴奋神经元的放电传递噪声）。在这里，我们回顾了支持这一假设的电生理证据，并讨论了多巴胺介导的对比度增强可能发生的潜在细胞机制。
