HOW DOES A FEAR ENGRAM INFLUENCE BRAIN AND BEHAVIOR STATES

Boer, Antje Rixt de (2023) HOW DOES A FEAR ENGRAM INFLUENCE BRAIN AND BEHAVIOR STATES. Master's Research Project 2, Biomedical Sciences.

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Abstract

Negative affective states are believed to contribute to psychiatric disorders. Studying the neural circuitry of fear behavior can provide insights into the underlying mechanisms of these disorders. This study aimed to explore the neuronal networks involved in fear memory and defensive behaviors by investigating how a fear engram influences both brain and behavior states. We did this by observing and manipulating the activity of relevant brain areas during the reactivation of fear memory-bearing engram cells. We optogenetically reactivated a tagged fear engram in the dentate gyrus (DG) subregion of the hippocampus and tested the effects of chemogenetic inhibition of the lateral hypothalamus (LHA) on light-induced freezing and cFos expression. Additionally, we examined light-induced freezing behavior and neuronal activity of the periaqueductal grey (PAG) during optogenetic reactivation of a tagged fear engram in differently-sized environments. Based on the results, we conclude that LHA activity is necessary for freezing behavior as inhibiting the LHA eliminated freezing behavior. We also conclude that animals freeze more in a small environment than in a large environment. Lastly, we conclude that the reception of a foot shock increases PAG neuronal activity. By unraveling the contributions of the LHA, PAG, and environmental factors in fear behavior, this research provides insights into the neural circuitry underlying fear.

Item Type:	Thesis (Master's Research Project 2)
Supervisor name:	Havekes, R.
Degree programme:	Biomedical Sciences
Thesis type:	Master's Research Project 2
Language:	English
Date Deposited:	16 Aug 2023 09:56
Last Modified:	16 Aug 2023 09:56
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/31198

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