Marks, Wendie

Stress can significantly affect neurobiological processes crucial for learning and memory. While repeated stress enhances fear memory, it impairs memory retrieval. In most studies, however, stress exposure typically preceded fear and extinction learning. Thus, the impact of previously acquired memories formed before exposure to stress is not well understood. The goal of this thesis is to examine how acute stress impacts the ability to retrieve previously acquired fear memories. The results showed that stress impaired recall of recent fear memories, but stress seven days after conditioning did not affect memory retrieval. Analysis of c-Fos expression revealed increased neuronal activity in the medial prefrontal cortex (mPFC) of rats exposed to stress. Additionally, stress exposure decreased mRNA expression of Reelin, a glycoprotein in the mPFC. Notably, administering recombinant Reelin improved fear memory recall. These findings highlight potential pathways for research and interventions on stress-induced memory impairments.

Author Keywords: c-Fos expression, Fear memory, Medial prefrontal cortex, Memory retrieval, Reelin, Stress