Jayden Barr | 2025 I.S. Symposium

Name: Jayden Barr
Title: The Effects of a 5-HT1A Receptor Agonist on Fear Memory Recall
Major: Neurobiology
Pathway: Public Health
Advisor: Alfredo Zúñiga

A primal instinct such as fear is essential for survival. However, the dysregulation of fear can lead to anxiety-like disorders, including post-traumatic stress disorder (PTSD) and anxiety. Serotonin (5-HT) is associated with a wide range of cognitive disorders, particularly PTSD, depression, and anxiety. The serotonin 1A receptor (5-HT1A) is abundant in brain regions linked to these cognitive disorders and memory functions, such as the dentate gyrus (DG). The goal of this study was to investigate the role of the 5-HT1A receptor agonist in fear memory recall and fear engrams. To test this, TRAP2 mice underwent contextual fear conditioning (CFC) and were injected with 5-HT1A agonist (8-OH-DPAT) or control vehicle (corn oil) before behavioral testing. The percentage of freezing behavior was analyzed within each group. Additionally, 4-OHT was administered during CFC training to “tag” neurons (ZsGreen+) activated during the acquisition of aversive memory. Neurons activated during behavioral testing were examined through immunohistochemistry for Arc, an immediate early gene. The overlap of these neuronal tags was analyzed to investigate the recall of the fear memory within the DG. Results indicated a significant decrease in freezing behavior when 8-OH-DPAT was administrated. Furthermore, there was no significant difference in the activation of ZsGreen+, Arc+, and the overlap of both ZsGreen+ and Arc+. These findings suggest that 5-HT1A receptors are involved in modulating fear memory, particularly evidenced by the reduction in anxiety-like behavior. However, the exact role of the 5-HT1A receptors in the modulation of the engram remains unclear and requires further investigation.

Posted in Symposium 2025 on May 1, 2025.