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ORCID
https://orcid.org/0000-0001-6110-1225
Access Type
Open Access Thesis
Document Type
thesis
Degree Program
Neuroscience & Behavior
Degree Type
Master of Science (M.S.)
Year Degree Awarded
2019
Month Degree Awarded
May
Abstract
This study examined the relationships between motivation and cognitive performance in male and female common marmosets (Callithrix jacchus). This question was driven by prior data from the Lacreuse lab showing a robust female impairment in reversal learning, as assessed by the number of trials needed to acquire a reversal following a simple discrimination between two stimuli. This thesis tested the hypothesis that the female impairment in reversal learning was mediated by deficits in motivation. Two sets of measures were used to test this hypothesis. I evaluated physical effort via testing on the progressive ratio (PR), a test that requires animals to produce an increasing number of responses to get a reward. Cognitive effort was evaluated through the number of refusals (aborted trials) produced during performance of a reversal. Because estrogen replacement was previously shown to impair reversal learning in ovariectomized females, I also examined whether PR performance was affected by estrogen levels in a subset of female subjects.
Contrary to my hypothesis, reversal learning was not significantly associated with cognitive or physical effort in either males or females. Estrogen levels did not significantly affect physical effort, but there was too much variability in a small sample of females for these results to be compelling. We conclude that the sex difference in reversal learning performance is unlikely to be mediated by sex differences in motivation. Instead females may be more likely than males to engage in habitual processes implicating the dorsal striatum, likely through the action of estrogens on this brain region.
DOI
https://doi.org/10.7275/14208676
First Advisor
Agnès Lacreuse
Second Advisor
David Moorman
Third Advisor
Matt Davidson
Recommended Citation
Carlotto, Alyssa, "Sex, Motivation, and Reversal Learning in the Common Marmoset (Callithrix jacchus)" (2019). Masters Theses. 762.
https://doi.org/10.7275/14208676
https://scholarworks.umass.edu/masters_theses_2/762