Campese Vincent D, Kim Jeanny, Lázaro-Muñoz Gabriel, Pena Lashawn, LeDoux Joseph E, Cain Christopher K
Center for Neural Science, New York University New York, NY, USA.
Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research Orangeburg, NY, USA.
Front Behav Neurosci. 2014 May 7;8:161. doi: 10.3389/fnbeh.2014.00161. eCollection 2014.
Aversive Pavlovian conditioned stimuli (CSs) elicit defensive reactions (e.g., freezing) and motivate instrumental actions like active avoidance (AA). Pavlovian reactions require connections between the lateral (LA) and central (CeA) nuclei of the amygdala, whereas AA depends on LA and basal amygdala (BA). Thus, the neural circuits mediating conditioned reactions and motivation appear to diverge in the amygdala. However, AA is not ideal for studying conditioned motivation, because Pavlovian and instrumental learning are intermixed. Pavlovian-to-instrumental transfer (PIT) allows for the study of conditioned motivation in isolation. PIT refers to the ability of a Pavlovian CS to modulate a separately-trained instrumental action. The role of the amygdala in aversive PIT is unknown. We designed an aversive PIT procedure in rats and tested the effects of LA, BA, and CeA lesions. Rats received Pavlovian tone-shock pairings followed by Sidman shock-avoidance training. PIT was assessed by comparing shuttling rates in the presence and absence of the tone. Tone presentations facilitated instrumental responding. Aversive PIT was abolished by lesions of LA or CeA, but was unaffected by lesions of BA. These results suggest that LA and CeA are essential for aversive conditioned motivation. More specifically, the results are consistent with a model of amygdala processing in which the CS is encoded in the LA and then, via connections to CeA, the motivation to perform the aversive task is enhanced. These findings have implications for understanding the contribution of amygdala circuits to aversive instrumental motivation, but also for the relation of aversive and appetitive behavioral control.
厌恶性巴甫洛夫条件刺激（CSs）会引发防御反应（如僵住），并激发诸如主动回避（AA）等工具性动作。巴甫洛夫反应需要杏仁核的外侧核（LA）和中央核（CeA）之间建立联系，而AA则依赖于LA和基底杏仁核（BA）。因此，介导条件反应和动机的神经回路在杏仁核中似乎是不同的。然而，AA并不适合用于研究条件动机，因为巴甫洛夫式学习和工具性学习相互交织。巴甫洛夫到工具性转移（PIT）使得能够单独研究条件动机。PIT是指巴甫洛夫CS调节单独训练的工具性动作的能力。杏仁核在厌恶性PIT中的作用尚不清楚。我们设计了一种大鼠厌恶性PIT程序，并测试了LA、BA和CeA损伤的影响。大鼠接受巴甫洛夫式音调-电击配对，随后进行西德曼回避电击训练。通过比较有音调与无音调时的穿梭速率来评估PIT。音调呈现促进了工具性反应。LA或CeA损伤消除了厌恶性PIT，但BA损伤对其没有影响。这些结果表明，LA和CeA对于厌恶性条件动机至关重要。更具体地说，这些结果与杏仁核处理模型一致，即CS在LA中编码，然后通过与CeA的连接，执行厌恶性任务的动机得到增强。这些发现不仅对于理解杏仁核回路对厌恶性工具性动机的贡献有意义，而且对于厌恶性和奖赏性行为控制之间的关系也有意义。
