本期Nature Communications上发表的一篇研究论文描述了负责在啮齿类动物的习惯性行动和目标性行动之间切换的神经过程。这些发现让我们对大脑处理现实中日常情况的连线方式有了新认识，同时也有可能提供有关在“强迫症”等疾病中被扰乱的系统的信息。
所有动物都不断会碰到需要对其行动的后果进行内部评估的情况，重要的是它们能够在习惯性行动和目标性行动之间进行切换。虽然主管目标性或习惯性行动的学习和执行的神经回路已被部分识别出来，但我们对这些行动和习惯是怎样在这些回路中被编码的却知之甚少。Christina Gremel和Rui Costa设计了一个新颖的小鼠行为任务：小鼠可以轻易地在用目标性策略或习惯性策略来执行压杠杆的动作之间进行切换，但在每一种情况下得到的奖励都是相同的。通过获取来自大脑的神经记录他们发现，大脑的“眶额皮层”和“背内侧纹状体”区域是向目标性行动的行为切换所必需的，而“背内侧纹状体”是向习惯性行动的行为切换所必需的。
虽然这些研究是用小鼠完成的，但作者希望这些发现将会加深我们对习惯和目标性行动之间的平衡被破坏的疾病如上瘾和强迫症等的认识。（生物谷 Bioon.com）
生物谷推荐的英文摘要
Nature Communications doi:10.1038/ncomms3264
Orbitofrontal and striatal circuits dynamically encode the shift between goal-directed and habitual actions
Christina M. Gremel & Rui M. Costa
Shifting between goal-directed and habitual actions allows for efficient and flexible decision making. Here we demonstrate a novel, within-subject instrumental lever-pressing paradigm, in which mice shift between goal-directed and habitual actions. We identify a role for orbitofrontal cortex (OFC) in actions following outcome revaluation, and confirm that dorsal medial (DMS) and lateral striatum (DLS) mediate different action strategies. Simultaneous in vivo recordings of OFC, DMS and DLS neuronal ensembles during shifting reveal that the same neurons display different activities depending on whether presses are goal-directed or habitual, with DMS and OFC becoming more and DLS less engaged during goal-directed actions. Importantly, the magnitude of neural activity changes in OFC following changes in outcome value positively correlates with the level of goal-directed behavior. Chemogenetic inhibition of OFC disrupts goal-directed actions, whereas optogenetic activation of OFC specifically increases goal-directed pressing. These results also reveal a role for OFC in action revaluation, which has implications for understanding compulsive behavior.
