The Effects of Early Life Stress on Adult Behavioral Flexibility in Alcohol-Seeking Behavior
Gabrielle Brown, George W. Wirtz, & Jennifer J. Quinn
Department of Psychology and Center for Neuroscience & Behavior
Miami University, Oxford, OH
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Research Team
Research Team
Gabrielle Brown
Gabrielle Brown
Psychological Science, Neuroscience co-major
George W. Wirtz
George W. Wirtz
Biological Science, Neuroscience co-major
Jennifer J. Quinn, Ph.D.
Jennifer J. Quinn, Ph.D.
Department of Psychology
Introduction
Introduction
The purpose of this study is to use reversal learning to explore the relationship between both chronic and acute early life stress (ELS) and behavioral flexibility.
Early life stress (ELS) is a traumatic or stressful experience occurring early in development, which can be categorized as either acute (isolated event) or chronic (ongoing), and has been linked with mental illness in adults [1][2].
Previous research in mice has shown a connection between chronic ELS and decreased behavioral flexibility, or the ability to learn new information in the face of change, but the relationship between acute ELS and behavioral flexibility is unknown [2].
We used reversal learning in order to test behavioral flexibility, where mice initially underwent operant conditioning in which they were required to perform a specific response (e.g., nosepoke) in order to earn a reinforcer. Then, the response requirement was reversed – the previously reinforced nosepoke no longer yielded a reinforcer, while a previously non-reinforced nosepoke then yielded reinforcement.
We expect to see reduced behavioral flexibility in both acute and chronic ELS groups. Further, we expect that the impairment in the chronic ELS group will be more robust than in the acute ELS group.
Research Question
Research Question
What is the relationship between acute early life stress (ELS) and behavioral and cognitive effects?
Methods
Methods
Male and female C57Bl/6 mice using a 2x2 factorial design, with test group and sex as factors. Groups:
Acute ELS, n=[x] per sex
Chronic ELS, n=[x] per sex
ELS conditions, exposed during a critical developmental period of youth prior to training and testing
Acute ELS, one footshock (x15) session
Chronic ELS, limited nesting and bedding
Behavioral training and testing:
Mice are maintained on a food restriction regime
Sucrose fading (11 days), increased exposure to ethanol
Magazine training (1 day), learn to nosepoke for ethanol
Acquisition training, 10% ethanol, ⅓ available nosepokes provide reinforcer
FR1 (9 days), 1:1 reinforcer/nosepoke ratio
Sucrose fades from 5%-2.5% in the first 6 days, then 0% sucrose/10% ethanol thereafter
Data is not collected for the first 6 days
FR3 (3 days), 1:3 reinforcer/nosepoke ratio
FR5 (3 days), 1:5 reinforcer/nosepoke ratio
Reversal training (28 days), location of correct nosepoke is changed
Analyze sucrose fading, instrumental acquisition, and reversal training data to determine the rate at which mice acquired the original nosepoke rule and then the reversed nosepoke rule to measure behavioral flexibility using a repeated-measures ANOVA.
Results
Results
Sucrose Fading
Figure 1. (A) shows the mean consumption (in grams) of the sucrose-ethanol solution over 11 days for each ELS group, with separate graphs for each sex. (B) a table of the sucrose and ethanol content (%) given to all mice for the 11 days of sucrose fading.
Instrumental Acquisition
Day * Stress [F(16, 464) = 1.814, p = 0.027]
Day * Stress [F(16, 464) = 1.790, p = 0.030]
Day * Sex * Stress [F(16, 464) = 2.105, p = 0.007]
Day * Sex [F(8, 456) = 3.055, p =0.002]
Figure 2. Each measure was collected during the 9 days of acquisition, where mice were given a 10% ethanol solution reinforcer. Acquisition is made up of x3 FR1, FR3, and FR5 days. Each measure compares the means of each ELS and sex group. (A) number of dipper presentations. (B) number of correct nosepoke entries. (C) number of incorrect nosepoke entries. (D) the number of times the mice entered the magazine chamber during a reinforcer presentation.
Instrumental Reversal
Figure 3. Each measure was collected during the 28 days of reversal training, where mice were given a 10% ethanol solution reinforcer on a FR1 schedule. (A) number of dipper presentations. (B) number of correct nosepoke entries. (C) number of incorrect nosepoke entries. (D) the number of times the mice entered the magazine chamber during a reinforcer presentation.
Discussion & Future Directions
Discussion & Future Directions
[Enter conclusions and future study. Adjust title as needed.]
The current data reflects an underpowered study that is in the process of being replicated to increase the number of mice in each group
There were no significant effects of sex or stress during the reversal phase, suggesting that ELS may not impair behvaioral flexibility, or the effects were too subtle to detect with this paradigm or number of mice
Significant effects of stress were observed in the number of reinforcers earned and the number of reinforced nosepokes during acquisition, suggesting that ELS may impair early learning stages rather than behavioral flexibility
The significant difference between males and females in their entries into the magazine dipper during acquisition may suggest there are sex differences in how mice are motivated to learn new behaviors and seek reinforcers
Prior research in this area suggests that ELS impairs behavioral flexibility, but the results presented here show possible impairment in early learning that does not carry over into adulthood.
Replications are necessary to confirm these findings.
The following is an image of poster presented at the 2026 Undergraduate Research Forum
Acknowledgements
Acknowledgements
We would like to thank Miami University, undergraduate funding, and the Quinn Behavioral Neuroscience Lab for making this research possible.
References
References
Cohen, R. A., Hitsman, B. L., Paul, R. H., McCaffery, J., Stroud, L., Sweet, L., Gunstad, J., Niaura, R., MaCfarlane, A., Bryant, R. A., & Gordon, E. (2006). Early life stress and adult emotional experience: An international perspective. The International Journal of Psychiatry in Medicine, 36(1), 35–52. https://doi.org/10.2190/5r62-9pqy-0nel-tlpa
Naninck, E. F.G., Hoeijmakers, L., Kakava-Georgiadou, N., Meesters, A., Lazic, S. E., Lucassen, P. J.& Korosi, A. (2015), Chronic early life stress alters developmental and adult neurogenesis and impairs cognitive function in mice. Hippocampus, 25, 309–328. doi:10.1002/hipo.22374
NACE Career Readiness Competencies
NACE Career Readiness Competencies
Throughout the research process, this research team has gained meaningful experience and new knowledge regarding NACE Career Readiness Competencies. We feel we have grown in our ability to communicate, use teamwork, and think critically while conducting our project.
Research Compliance Protocols
Research Compliance Protocols
This research was approved by the Miami University IACUC (protocol # 1120_2028_Dec ).
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