Lissek Silke, Klass Anne, Tegenthoff Martin
Department of Neurology, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany.
Front Behav Neurosci. 2020 Mar 27;14:43. doi: 10.3389/fnbeh.2020.00043. eCollection 2020.
The renewal effect of extinction demonstrates the context-dependency of extinction learning. It is defined as the recovery of an extinguished response occurring when the contexts of extinction and recall differ. Behavioral studies showed that modulating context relevance can strengthen context-specific responses. In our fMRI study, we investigated to what extent a modulation of context salience can alter renewal levels and provide additional information about the neural basis for renewal. In a within-subjects design, participants completed two sessions of an associative learning task in randomized order. In the salient condition (SAL), a context was presented alone at the start of each trial, before being presented together with the stimulus. The regular condition (REG) contained no context-alone phase. In about one-third of participants (SWITCH), the context salience modulation significantly increased renewal rates in the SAL compared to the REG condition. The other participants showed either renewal (REN) or no renewal (NoREN) in both conditions. The modulation did not significantly affect learning performance during the initial forming of associations or extinction learning. In the SWITCH group, activation in left opercular inferior frontal gyrus (iFG) during the recall phase was associated with a renewal effect, together with activity in the bilateral posterior hippocampus and ventromedial prefrontal cortex (vmPFC). Also during the extinction phase, left opercular iFG activation was higher in groups exhibiting renewal in recall, irrespective of the context salience modulation. Besides confirming the participation of vmPFC in extinction recall, our findings provide novel insights regarding an as yet undetected, potentially important role for renewal-supporting processes in left iFG during extinction learning and recall, which are presumably based on the region's proposed function of evaluating competing response options under conditions of ambiguity.
消退的恢复效应表明了消退学习的情境依赖性。它被定义为当消退和回忆的情境不同时，已消退反应的恢复。行为学研究表明，调节情境相关性可以增强特定情境的反应。在我们的功能磁共振成像（fMRI）研究中，我们调查了情境显著性的调节在多大程度上可以改变恢复水平，并提供有关恢复的神经基础的额外信息。在一项被试内设计中，参与者以随机顺序完成了两个阶段的联想学习任务。在显著条件（SAL）下，每次试验开始时先单独呈现一个情境，然后再与刺激一起呈现。常规条件（REG）没有单独呈现情境的阶段。在大约三分之一的参与者（SWITCH）中，与REG条件相比，情境显著性调节显著提高了SAL中的恢复率。其他参与者在两种条件下均表现出恢复（REN）或无恢复（NoREN）。这种调节在联想最初形成或消退学习期间对学习表现没有显著影响。在SWITCH组中，回忆阶段左侧额下回岛盖部（iFG）的激活与恢复效应相关，同时双侧后海马体和腹内侧前额叶皮质（vmPFC）也有活动。同样在消退阶段，无论情境显著性调节如何，在回忆中表现出恢复的组中左侧额下回岛盖部的激活更高。除了证实vmPFC参与消退回忆外，我们的研究结果还提供了关于在消退学习和回忆期间左侧iFG中尚未被发现的、可能对恢复支持过程起重要作用的新见解，这可能基于该区域在模糊条件下评估竞争反应选项的假定功能。
