Reward is a vastly complex process, integrating diverse brain regions and neurotransmitters to modulate higher-order vertebrate behavior. Often studied utilizing unnatural drugs of abuse (cocaine, methamphetamines, alcohol), reward research is relevant to substance abuse disorders and conditions involving dysfunctional reward circuitry (depressive disorders, schizophrenia). The present study, however, aimed to approach reward with a naturally rewarding substance: chocolate. Using five milk chocolate chips as a natural reward, I sought to evaluate the ability of mice to develop conditioned place preference to a context paired with this reward. Subjecting male and female C57BL/6J male mice (n = 16) to a ten-day conditioned place preference paradigm, it was hypothesized that the experimental mice would develop preference for the CS+ conditioning environment. Analyzing the percent preference data, I found no signicant conditioning in any mice, however, I observed sex dierences within the experimental mice. The experimental male mice exhibited increased preference for the CS+ conditioning environment in comparison to the experimental females. Furthermore, the male mice, overall, consumed more of the natural reward than the females during conditioning. My data suggests that conditioning was more successful in the male mice, indicating that sex dierences may underlie natural reward-induced CPP. In follow up research, I would like to further elucidate the identity of active neurons through fluorescent microscopy techniques and assess the role of various reward doses in natural reward.


Zúñiga, Alfredo




Behavioral Neurobiology | Cognitive Neuroscience

Publication Date


Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis


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