当执行一个行为时，动作序列的适当起动和终止至关重要；这个过程在帕金森氏症和亨廷顿症等“黑质纹状体”疾病中不能正常进行。
人们对主管一个固定行为模式的学习和执行的神经机制还不是很了解，但Xin Jin 和Rui Costa揭示了在任务训练过程中基底神经节回路中所出现的起动/停止神经激发模式。小鼠能够学会按自己确定的进度非常精确地执行固定数量的一组重复性动作――它们要完成的任务是压杠杆，完成之后可以获得蔗糖作为奖励。
利用这一任务，Jin和Costa发现，“黑质纹状体”回路中很多神经元能够选择性地对每组被执行的动作发出自我抑制或自我终止的信号。这些回路的基因改动破坏起动/停止的执行，影响小鼠的表现。这一发现为特定神经活动和任务学习之间的因果关系提供了证据。
推荐原文出处：
Nature doi:10.1038/nature09263
Start/stop signals emerge in nigrostriatal circuits during sequence learning
Xin Jin" Rui M. Costa
Learning new action sequences subserves a plethora of different abilities such as escaping a predator, playing the piano, or producing fluent speech. Proper initiation and termination of each action sequence is critical for the organization of behaviour, and is compromised in nigrostriatal disorders like Parkinson’s and Huntington’s diseases. Using a self-paced operant task in which mice learn to perform a particular sequence of actions to obtain an outcome, we found neural activity in nigrostriatal circuits specifically signalling the initiation or the termination of each action sequence. This start/stop activity emerged during sequence learning, was specific for particular actions, and did not reflect interval timing, movement speed or action value. Furthermore, genetically altering the function of striatal circuits disrupted the development of start/stop activity and selectively impaired sequence learning. These results have important implications for understanding the functional organization of actions and the sequence initiation and termination impairments observed in basal ganglia disorders.
