Using optogenetics to test the role of auditory cortex in memory retrieving Restricted; Files Only

Chengcheng Yang (Fall 2023)

Permanent URL: https://etd.library.emory.edu/concern/etds/df65v9101?locale=en
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Abstract

Understanding the role of the auditory cortex (ACx) in auditory information retrieval is critical for insights into cognitive processes and sensory integration. This study utilized optogenetic tools to transiently inhibit the ACx in mice trained to use auditory cues for pup retrieval, aiming to discern the functional significance of the ACx in memory retrieval. Inexperienced female CBA/CaJ mice underwent a series of trainings in a T-maze, followed by assessments under conditions of optogenetic ACx inactivation.

The experiment was conducted in two conditions: Light (with optogenetic stimulation) and No- light (without stimulation), serving as a control. Subjects' performances were analyzed using binomial tests to compare success rates against chance, and chi-square tests to compare performances across conditions. Results indicated that under non-light conditions, both subjects displayed a proficiency in auditory cue-based localization, with performances significantly above chance (p < 0.001, while during Light trials, subject's success rate did not differ significantly from chance.

The study's findings underscore the complexity of the ACx's involvement in auditory processing, highlighted by the variability in response to optogenetic inhibition. This variability could suggest individual differences in neural circuitry or sensitivity to optical stimulation. The results emphasize the need for further research to refine optogenetic applications, understand individual variability, and explore the intricate relationship between neural circuitry, sensory processing, and behavior. 

Table of Contents

Table of Contents

Introduction ...................................................................................................................................................1 Method...........................................................................................................................................................2 Animals............................................................................................................................................................... 2

T-maze setup .................................................................................................................................................... 3

Viral Injection................................................................................................................................................... 3

Ferrule Implantation ..................................................................................................................................... 4

Habituation ....................................................................................................................................................... 4 Stimuli................................................................................................................................................................. 5

Behavioral Training ....................................................................................................................................... 5

Testing Memory Retrieval with Optogenetic Inactivation................................................................ 6

Statistics ............................................................................................................................................................. 6

Binomial Test.........................................................................................................................................................................................6

Chi-Square Test.....................................................................................................................................................................................7

Results ...........................................................................................................................................................7

Optogenetic inactivation of ACx impaired memory retrieval.......................................................... 8

Discussion.................................................................................................................................................. 10

Interpretation of Optogenetic Influence...............................................................................................10

Innate Auditory Processing Proficiency................................................................................................11

Individual Variability in Response to Optogenetic Stimulation ...................................................12

Implications for Optogenetic Applications ..........................................................................................12

Future Directions .................................................................................................................................... 12

Figure 1: Training Protocol for Auditory Cue-Based Localization in Subject Mice.......... 14

Figure 2: Depiction of ACx Craniotomy and Optogenetic Vector Infusion .......................... 15

Figure 3: Percentage of correct localization ................................................................................. 16

References ................................................................................................................................................. 17 

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