Laboratory of Systems Neuroscience, National Institute of Mental Health, Bethesda, Maryland 20892, USA.
Annu Rev Neurosci. 2011;34:441-66. doi: 10.1146/annurev-neuro-061010-113641.
The basal ganglia are a chain of subcortical nuclei that facilitate action selection. Two striatal projection systems--so-called direct and indirect pathways--form the functional backbone of the basal ganglia circuit. Twenty years ago, investigators proposed that the striatum's ability to use dopamine (DA) rise and fall to control action selection was due to the segregation of D(1) and D(2) DA receptors in direct- and indirect-pathway spiny projection neurons. Although this hypothesis sparked a debate, the evidence that has accumulated since then clearly supports this model. Recent advances in the means of marking neural circuits with optical or molecular reporters have revealed a clear-cut dichotomy between these two cell types at the molecular, anatomical, and physiological levels. The contrast provided by these studies has provided new insights into how the striatum responds to fluctuations in DA signaling and how diseases that alter this signaling change striatal function.
基底神经节是一连串的皮质下核团，有助于动作选择。两个纹状体投射系统——所谓的直接和间接通路——构成了基底神经节回路的功能主干。二十年前，研究人员提出，纹状体利用多巴胺（DA）的上升和下降来控制动作选择的能力，是由于直接和间接通路棘突投射神经元中 D1 和 D2 DA 受体的分离。尽管这一假设引发了一场争论，但此后积累的证据清楚地支持了这一模型。利用光学或分子报告器标记神经回路的新方法的进展，在分子、解剖和生理水平上揭示了这两种细胞类型之间明显的二分法。这些研究提供的对比为纹状体如何响应 DA 信号波动以及改变这种信号的疾病如何改变纹状体功能提供了新的见解。
