Cole S, Hobin M P, Petrovich G D
Department of Psychology, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467-3807, USA.
Department of Psychology, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467-3807, USA.
Neuroscience. 2015 Feb 12;286:187-202. doi: 10.1016/j.neuroscience.2014.11.026. Epub 2014 Nov 22.
The amygdala, prefrontal cortex, striatum and other connected forebrain areas are important for reward-associated learning and subsequent behaviors. How these structurally and functionally dissociable regions are recruited during initial learning, however, is unclear. Recently, we showed amygdalar nuclei were differentially recruited across different stages of cue-food associations in a Pavlovian conditioning paradigm. Here, we systematically examined Fos induction in the forebrain, including areas associated with the amygdala, during early (day 1) and late (day 10) training sessions of cue-food conditioning. During training, rats in the conditioned group received tone-food pairings, while controls received presentations of the tone alone in the conditioning chamber followed by food delivery in their home cage. We found that a small subset of telencephalic and hypothalamic regions were differentially recruited during the early and late stages of training, suggesting evidence of learning-induced plasticity. Initial tone-food pairings recruited solely the amygdala, while late tone-food pairings came to induce Fos in distinct areas within the medial and lateral prefrontal cortex, the dorsal striatum, and the hypothalamus (lateral hypothalamus and paraventricular nucleus). Furthermore, within the perifornical lateral hypothalamus, tone-food pairings selectively recruited neurons that produce the orexigenic neuropeptide orexin/hypocretin. These data show a functional map of the forebrain areas recruited by appetitive associative learning and dependent on experience. These selectively activated regions include interconnected prefrontal, striatal, and hypothalamic regions that form a discrete but distributed network that is well placed to simultaneously inform cortical (cognitive) processing and behavioral (motivational) control during cue-food learning.
杏仁核、前额叶皮质、纹状体以及其他相连的前脑区域对于与奖赏相关的学习及后续行为非常重要。然而，在初始学习过程中这些在结构和功能上可分离的区域是如何被募集的尚不清楚。最近，我们发现在经典条件反射范式中，杏仁核核团在提示-食物关联的不同阶段被差异性地募集。在此，我们系统地检查了在提示-食物条件反射的早期（第1天）和晚期（第10天）训练期间前脑中的即早基因Fos的诱导情况，包括与杏仁核相关的区域。在训练期间，条件组的大鼠接受音调-食物配对，而对照组在条件反射箱中仅接受音调呈现，随后在其笼舍中给予食物。我们发现一小部分端脑和下丘脑区域在训练的早期和晚期被差异性地募集，提示学习诱导可塑性的证据。最初的音调-食物配对仅募集杏仁核，而后期的音调-食物配对开始在内侧和外侧前额叶皮质、背侧纹状体以及下丘脑（外侧下丘脑和室旁核）的不同区域诱导Fos。此外，在穹窿周外侧下丘脑内，音调-食物配对选择性地募集了产生促食欲神经肽食欲素/下丘脑泌素的神经元。这些数据显示了由食欲性联想学习募集并依赖于经验的前脑区域的功能图谱。这些选择性激活的区域包括相互连接的前额叶、纹状体和下丘脑区域，它们形成了一个离散但分布广泛的网络，该网络非常适合在提示-食物学习过程中同时为皮质（认知）加工和行为（动机）控制提供信息。
