Department of Psychology, Stony Brook University, 100 Nicolls Rd., Stony Brook, NY, 11794, USA.
Sci Rep. 2022 Aug 11;12(1):13703. doi: 10.1038/s41598-022-17895-5.
Post-traumatic stress disorder (PTSD) is characterized by an impaired ability to extinguish fear responses to trauma-associated cues. Studies in humans and non-human animals point to differences in the engagement of certain frontal cortical regions as key mediators determining whether or not fear extinction is successful, however the neural circuit interactions that dictate the differential involvement of these regions are not well understood. To better understand how individual differences in extinction recall are reflected in differences in neural circuit activity, we labeled projections to the infralimbic cortex (IL) in rats using a retrograde tracer and compared neural activity within, and outside, of IL-projecting neurons. We analyzed these data in groups separated on the basis of how well rats retained extinction memory. We found that within IL-projecting cells, neurons in the posterior paraventricular thalamus showed heightened activity in rats that showed good extinction recall. Outside of the IL-projecting cells, increased Fos activity was observed in good extinction rats in select regions of the claustrum and ventral hippocampus. Our results indicate that differences in extinction recall are associated with a specific pattern of neural activity both within and outside of projections to the IL.
创伤后应激障碍（PTSD）的特征是创伤相关线索引起的恐惧反应难以消除。人类和非人类动物的研究指出，特定额皮质区域的参与程度不同，是决定恐惧是否能成功消除的关键中介因素，然而，决定这些区域不同参与程度的神经回路相互作用尚不清楚。为了更好地理解在神经回路活动中，消退回忆的个体差异是如何反映的，我们使用逆行示踪剂标记大鼠的下边缘皮质（IL）投射，并比较了 IL 投射神经元内和神经元外的神经活动。我们根据大鼠保留消退记忆的程度将这些数据分组进行分析。我们发现，在 IL 投射细胞内，丘脑后室旁核的神经元在消退记忆表现良好的大鼠中表现出更高的活性。在 IL 投射细胞外，在消退记忆良好的大鼠中，在屏状核和腹侧海马的特定区域观察到 Fos 活性增加。我们的结果表明，消退记忆的差异与 IL 投射内和投射外的特定神经活动模式有关。
