Schultz Douglas H, Balderston Nicholas L, Helmstetter Fred J
Department of Psychology, University of Wisconsin-Milwaukee Milwaukee, WI, USA.
Front Hum Neurosci. 2012 Aug 23;6:242. doi: 10.3389/fnhum.2012.00242. eCollection 2012.
Neural plasticity in the amygdala is necessary for the acquisition and storage of memory in Pavlovian fear conditioning, but most neuroimaging studies have focused only on stimulus-evoked responses during the conditioning session. This study examined changes in the resting-state functional connectivity (RSFC) of the amygdala before and after Pavlovian fear conditioning, an emotional learning task. Behavioral results from the conditioning session revealed that participants learned normally and fMRI data recorded during learning identified a number of stimulus-evoked changes that were consistent with previous work. A direct comparison between the pre- and post-conditioning amygdala connectivity revealed a region of dorsal prefrontal cortex (PFC) in the superior frontal gyrus that showed a significant increase in connectivity following the conditioning session. A behavioral measure of explicit memory performance was positively correlated with the change in amygdala connectivity within a neighboring region in the superior frontal gyrus. Additionally, an implicit autonomic measure of conditioning was positively correlated with the change in connectivity between the amygdala and the anterior cingulate cortex (ACC). The resting-state data show that amygdala connectivity is altered following Pavlovian fear conditioning and that these changes are also related to behavioral outcomes. These alterations may reflect the operation of a consolidation process that strengthens neural connections to support memory after the learning event.
杏仁核中的神经可塑性对于巴甫洛夫恐惧条件反射中记忆的获取和存储是必要的，但大多数神经影像学研究仅关注条件反射过程中刺激诱发的反应。本研究考察了在巴甫洛夫恐惧条件反射（一种情绪学习任务）前后杏仁核静息态功能连接（RSFC）的变化。条件反射实验的行为结果显示，参与者学习正常，学习过程中记录的功能磁共振成像（fMRI）数据识别出一些与先前研究一致的刺激诱发变化。对条件反射前后杏仁核连接性的直接比较显示，额上回背侧前额叶皮质（PFC）的一个区域在条件反射实验后连接性显著增加。明确记忆表现的行为测量与额上回相邻区域内杏仁核连接性的变化呈正相关。此外，条件反射的隐式自主测量与杏仁核和前扣带回皮质（ACC）之间连接性的变化呈正相关。静息态数据表明，巴甫洛夫恐惧条件反射后杏仁核连接性发生改变，且这些变化也与行为结果相关。这些改变可能反映了巩固过程的运作，该过程在学习事件后加强神经连接以支持记忆。
