Department of Brain and Cognitive Sciences and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Neurophysiol. 2009 Oct;102(4):2142-60. doi: 10.1152/jn.00522.2009. Epub 2009 Jul 22.
The sensorimotor striatum, as part of the brain's habit circuitry, has been suggested to store fixed action values as a result of stimulus-response learning and has been contrasted with a more flexible system that conditionally assigns values to behaviors. The stability of neural activity in the sensorimotor striatum is thought to underlie not only normal habits but also addiction and clinical syndromes characterized by behavioral fixity. By recording in the sensorimotor striatum of mice, we asked whether neuronal activity acquired during procedural learning would be stable even if the sensory stimuli triggering the habitual behavior were altered. Contrary to expectation, both fixed and flexible activity patterns appeared. One, representing the global structure of the acquired behavior, was stable across changes in task cuing. The second, a fine-grain representation of task events, adjusted rapidly. Such dual forms of representation may be critical to allow motor and cognitive flexibility despite habitual performance.
感觉运动纹状体作为大脑习惯回路的一部分，被认为可以通过刺激-反应学习来存储固定的动作值，并与更灵活的系统形成对比，后者可以根据行为条件分配值。感觉运动纹状体中神经活动的稳定性不仅是正常习惯的基础，也是成瘾和以行为固定为特征的临床综合征的基础。通过在小鼠的感觉运动纹状体中进行记录，我们询问在习惯行为的感觉刺激发生变化的情况下，程序性学习过程中获得的神经元活动是否仍然稳定。与预期相反，固定和灵活的活动模式都出现了。一种模式代表了习得行为的整体结构，在任务提示的变化下保持稳定。第二种模式则是任务事件的精细粒度表示，能够快速调整。这种双重表示形式可能对于在保持习惯性表现的同时实现运动和认知灵活性至关重要。
