Abstract
Anxiety-related disorders respond to cognitive behavioral therapies, which involved the medial prefrontal cortex (mPFC). Previous studies have suggested that subregions of the mPFC have different and even opposite roles in regulating innate anxiety. However, the specific causal targets of their descending projections in modulating innate anxiety and stress-induced anxiety have yet to be fully elucidated. Here, we found that among the various downstream pathways of the prelimbic cortex (PL), a subregion of the mPFC, PL-mediodorsal thalamic nucleus (MD) projection and PL-ventral tegmental area (VTA) projection exhibited antagonistic effects on anxiety-like behavior, while the PL-MD projection but not PL-VTA projection was necessary for the animal to guide anxiety-related behavior. In addition, MD-projecting PL neurons bidirectionally regulated remote but not recent fear memory retrieval. Notably, restraint stress induced high-anxiety state accompanied by strengthening the excitatory inputs onto MD-projecting PL neurons, and inhibiting PL-MD pathway rescued the stress-induced anxiety. Our findings reveal that the activity of PL-MD pathway may be an essential factor to maintain certain level of anxiety, and stress increased the excitability of this pathway, leading to inappropriate emotional expression, and suggest that targeting specific PL circuits may aid the development of therapies for the treatment of stress-related disorders.
Significance statement This study provides insight into PL downstream pathways for regulating innate and stress-induced anxiety-like behavior. We reported that PL-mediodorsal thalamic nucleus (MD) projection and PL-ventral tegmental area (VTA) projection exhibited antagonistic effects on anxiety-like behavior, while the PL-MD projection but not PL-VTA projection was necessary for the animal to guide anxiety-related behavior. In addition, this study provides definite evidence that MD-projecting PL neurons bidirectionally regulated remote fear memory retrieval and concordant with a role for the PL-MD in anxiety. Moreover, this study is the first demonstration that restraint stress induced high-anxiety state accompanied by strengthening the excitatory inputs onto MD-projecting PL neurons, and inhibiting PL-MD pathway rescued the stress-induced anxiety.
Footnotes
The authors declare no competing financial interests.
This work was supported by grants from the National Key R&D Program of China (2021ZD0202704, to TMG and 2022ZD0214300, to YHC); the National Natural Science Foundation of China (82090032 and 31830033, to TMG; 32271014, to YHC); the Key Area Research and Development Program of Guangdong Province (2018B030334001 and 2018B030340001, to TMG); Guangdong-Hong Kong Joint Laboratory for Psychiatric Disorders (2023B1212120004) and the Science and Technology Program of Guangzhou (202007030013, to TMG; SL2022A04J00182, to YHC).
↵#These authors contributed equally.
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