Lissek Silke, Tegenthoff Martin
Department of Neurology, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany.
Front Behav Neurosci. 2024 Feb 26;18:1307825. doi: 10.3389/fnbeh.2024.1307825. eCollection 2024.
Renewal of extinguished responses is associated with higher activity in specific extinction-relevant brain regions, i.e., hippocampus (HC), inferior frontal gyrus (IFG), and ventromedial PFC (vmPFC). HC is involved in processing of context information, while IFG and vmPFC use such context information for selecting and deciding among competing response options. However, it is as yet unknown to what extent trials with changed versus unchanged outcome, or extinction trials that evoke renewal (i.e., extinction context differs from acquisition and test context: ABA trials) and trials that do not (i.e., same context in all phases: AAA trials) are represented differentially in extinction-relevant brain regions.
In this study, we applied representational similarity analysis (RSA) to determine differences in neural representations of these trial types and their relationship to extinction error rates and renewal level.
Overall, individuals with renewal (REN) and those without (NoREN) did not differ significantly in their discrimination levels between ABA and AAA extinction trials, with the exception of right posterior HC, where REN exhibited more pronounced context-related discrimination. In addition, higher dissimilarity of representations in bilateral posterior HC, as well as in several IFG regions, during extinction learning was linked to lower ABA renewal rates. Both REN and NoREN benefitted from prediction error feedback from ABA extinction errors for context- and outcome-related discrimination of trials in IFG, vmPFC, and HC, but only the NoREN group also benefitted from error feedback from AAA extinction errors.
Thus, while in both groups the presence of a novel context supported formation of distinct representations, only in NoREN the expectancy violation of the surprising change of outcome alone had a similar effect. In addition, only in NoREN context-related discrimination was linked to error feedback in vmPFC. In summary, the findings show that context- and outcome-related discrimination of trials in HC, vmPFC, and IFG is linked to extinction learning errors, regardless of renewal propensity, and at the same time point towards differential context processing strategies in REN and NoREN. Moreover, better discrimination of context-related trials during extinction learning promotes less renewal during extinction recall, suggesting that renewal may be related to suboptimal context-related trial discrimination.
消退反应的恢复与特定的与消退相关的脑区（即海马体（HC）、额下回（IFG）和腹内侧前额叶皮质（vmPFC））的更高活动有关。海马体参与情境信息的处理，而额下回和腹内侧前额叶皮质利用此类情境信息在相互竞争的反应选项中进行选择和决策。然而，尚不清楚结果改变与未改变的试验，或者引发恢复的消退试验（即消退情境与习得和测试情境不同：ABA试验）和未引发恢复的试验（即所有阶段情境相同：AAA试验）在与消退相关的脑区中在多大程度上有不同的表征。
在本研究中，我们应用表征相似性分析（RSA）来确定这些试验类型的神经表征差异及其与消退错误率和恢复水平的关系。
总体而言，有恢复现象（REN）和无恢复现象（NoREN）的个体在ABA和AAA消退试验之间的辨别水平上没有显著差异，但右侧后海马体除外，在该区域有恢复现象的个体表现出更明显的与情境相关的辨别。此外，在消退学习期间，双侧后海马体以及几个额下回区域的表征更高的不相似性与更低的ABA恢复率相关。有恢复现象和无恢复现象的个体都受益于来自ABA消退错误的预测误差反馈，用于额下回、腹内侧前额叶皮质和海马体中与情境和结果相关的试验辨别，但只有无恢复现象的组也受益于来自AAA消退错误的误差反馈。
因此，虽然在两组中新颖情境的存在都支持形成不同的表征，但只有在无恢复现象的个体中，仅结果的意外变化所导致的预期违背才有类似的效果。此外，只有在无恢复现象的个体中，与情境相关的辨别才与腹内侧前额叶皮质中的误差反馈相关。总之，研究结果表明，海马体、腹内侧前额叶皮质和额下回中与情境和结果相关的试验辨别与消退学习错误有关，无论恢复倾向如何，同时也指向有恢复现象和无恢复现象的个体在情境处理策略上的差异。此外，在消退学习期间对与情境相关的试验有更好的辨别会促进消退回忆期间更少的恢复，这表明恢复可能与次优的与情境相关的试验辨别有关。
