The role of 40hz oscillation at Basolateral Amygdala in mediating the retrieval of extinction Memory
Chen, Yifan
2022
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While exposure therapy is the standard of care for post-traumatic stress disorder, it rarely leads to a full recovery. Thus, it is imperative to investigate the biological mechanisms underlying fear extinction to understand the power and limitations of exposure therapy. During extinction learning, an analogous process of exposure therapy in animals, a new extinction/safety memory is formed and ... read morecompetes with the original fear memory for retrieval. The current study aimed to probe the role of gamma range (30 -100+ Hz) oscillation at the basolateral amygdala (BLA), a crucial brain region for valanced memory learning in supporting such competition. Unpublished data in the Reijmers Lab suggested the power of 40 Hz oscillations at BLA was increased during extinction learning and retrieval of the extinction memory. This suggests a role of BLA 40 Hz in biasing the retrieval of extinction over fear memory. To explore this hypothesis, the fear level, as quantified by the freezing level of mice, was measured during exogenously induced 40 Hz oscillation by optogenetic manipulation of Parvalbumin (PV) interneurons at the BLA. The level of fear reduction at 40Hz was further compared with reduction induced by different frequencies of stimulation and at different memory states to determine whether 40 Hz oscillation uniquely in the gamma range bias the retrieval of extinction memory. However, even after accounting for the extinction learning difference in individuals, results showed that 40 Hz failed to induce significant fear reduction compared to other stimulation conditions. The insignificant effect of 40 Hz oscillation observed in the current data was most likely due to a lack of subjects. The inclusion of more individuals is necessary to truly determine the role of BLA 40Hz oscillation in extinction learning.
Thesis (B.S.)--Tufts University, 2022.
Submitted to the Dept. of Psychology.
Advisors: Leon Reijmers and Elizabeth Race.
Keywords: Optogenetic, PTSD, extinction learning, gamma oscillations, exposure therapy.read less - ID:
- dr26zc223
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