Psychological Science Faculty Publications and Presentations
Document Type
Article
Publication Date
7-26-2024
Abstract
The hippocampus has a central role in regulating contextual processes in memory. We have shown that pharmacological inactivation of ventral hippocampus (VH) attenuates the context-dependence of signaled active avoidance (SAA) in rats. Here, we explore whether the VH mediates intertrial responses (ITRs), which are putative unreinforced avoidance responses that occur between trials. First, we examined whether VH inactivation would affect ITRs. Male rats underwent SAA training and subsequently received intra-VH infusions of saline or muscimol before retrieval tests in the training context. Rats that received muscimol performed significantly fewer ITRs, but equivalent avoidance responses, compared to controls. Next, we asked whether chemogenetic VH activation would increase ITR vigor. In male and female rats expressing excitatory (hM3Dq) DREADDs, systemic CNO administration produced a robust ITR increase that was not due to nonspecific locomotor effects. Then, we examined whether chemogenetic VH activation potentiated ITRs in an alternate (non-training) test context and found it did. Finally, to determine if context-US associations mediate ITRs, we exposed rats to the training context for three days after SAA training to extinguish the context. Rats submitted to context extinction did not show a reliable decrease in ITRs during a retrieval test, suggesting that context-US associations are not responsible for ITRs. Collectively, these results reveal an important role for the VH in context-dependent ITRs during SAA. Further work is required to explore the neural circuits and associative basis for these responses, which may be underlie pathological avoidance that occurs in humans after threat has passed.
Recommended Citation
Oleksiak, C. R., Plas, S. L., Carriaga, D., Vasudevan, K., Maren, S., & Moscarello, J. M. (2024). Ventral hippocampus mediates inter-trial responding in signaled active avoidance. Behavioural Brain Research, 115071. https://doi.org/10.1016/j.bbr.2024.115071
Publication Title
Behavioural Brain Research
DOI
https://doi.org/10.1016/j.bbr.2024.115071
Comments
Student publication. Original published version available at https://doi.org/10.1016/j.bbr.2024.115071