Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida.
J Neurophysiol. 2021 Jan 1;125(1):166-183. doi: 10.1152/jn.00495.2020. Epub 2020 Nov 11.
The ventral striatum regulates motivated behaviors that are essential for survival. The ventral striatum contains both the nucleus accumbens (NAc), which is well established to contribute to motivated behavior, and the adjacent tubular striatum (TuS), which is poorly understood in this context. We reasoned that these ventral striatal subregions may be uniquely specialized in their neural representation of goal-directed behavior. To test this, we simultaneously examined TuS and NAc single-unit activity as male mice engaged in a sucrose self-administration task, which included extinction and cue-induced reinstatement sessions. Although background levels of activity were comparable between regions, more TuS neurons were recruited upon reward-taking, and among recruited neurons, TuS neurons displayed greater changes in their firing during reward-taking and extinction than those in the NAc. Conversely, NAc neurons displayed greater changes in their firing during cue-reinstated reward-seeking. Interestingly, at least in the context of this behavioral paradigm, TuS neural activity predicted reward-seeking, whereas NAc activity did not. Together, by directly comparing their dynamics in several behavioral contexts, this work reveals that the NAc and TuS ventral striatum subregions distinctly represent reward-taking and reward-seeking. The ventral striatum, considered the reward circuitry "hub," is composed of two regions: the NAc, which is well established for its role in reward processing, and the TuS, which has been largely excluded from such studies. This study provides a first step in directly contextualizing the TuS's activity in relation to that in the NAc and, by doing so, establishes a critical framework for future research seeking to better understand the brain basis for drug addiction.
腹侧纹状体调节生存所必需的动机行为。腹侧纹状体包含伏隔核（NAc），它对动机行为有贡献，还有相邻的管状纹状体（TuS），但在这种情况下了解甚少。我们推断这些腹侧纹状体亚区可能在其对目标导向行为的神经表现上具有独特的专业化。为了验证这一点，我们同时检查了雄性小鼠在蔗糖自我给药任务中的 TuS 和 NAc 单个神经元的活动，该任务包括消退和线索诱导的复吸阶段。尽管区域之间的背景活动水平相当，但在取食奖励时，TuS 神经元的募集更多，在募集的神经元中，TuS 神经元在取食奖励和消退期间的放电变化大于 NAc 神经元。相反，在 cue-reinstated 奖励寻求期间，NAc 神经元的放电变化更大。有趣的是，至少在这种行为范式的背景下，TuS 神经元活动预测了奖励寻求，而 NAc 活动则没有。总的来说，通过直接比较它们在几种行为背景下的动态，这项工作揭示了 NAc 和 TuS 腹侧纹状体亚区明显代表了奖励取食和奖励寻求。腹侧纹状体被认为是奖励回路的“枢纽”，由两个区域组成：NAc，其在奖励处理中作用已得到充分确立，以及 TuS，其在很大程度上被排除在这些研究之外。这项研究为直接将 TuS 的活动与 NAc 的活动联系起来提供了第一步，并为此建立了一个重要的框架，以促进未来的研究，从而更好地了解药物成瘾的大脑基础。
