Females in the forefront: time-based intervention effects on impulsive choice and interval timing in female rats

Animal Cognition, Aug 2018

Impulsive choice has been implicated in substance abuse, gambling, obesity, and other maladaptive behaviors. Deficits in interval timing may increase impulsive choices, and therefore, could serve as an avenue through which suboptimal impulsive choices can be moderated. Temporal interventions have successfully attenuated impulsive choices in male rats, but the efficacy of a temporal intervention has yet to be assessed in female rats. As such, this experiment examined timing and choice behavior in female rats, and evaluated the ability of a temporal intervention to mitigate impulsive choice behavior. The temporal intervention administered in this study was successful in reducing impulsive choices compared to a control group. Results of a temporal bisection task indicated that the temporal intervention increased long responses at the shorter durations. Further, results from the peak trials within the choice task combined with the progressive interval task suggest that the intervention increased sensitivity to delay and enhanced timing confidence. Overall, these results indicate that a temporal intervention can be a successful avenue for reducing impulsive choice behavior in female rats, and could contribute to the development of behavioral interventions to prevent impulsive choice and maladaptive behaviors that can be applied to both sexes.

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Females in the forefront: time-based intervention effects on impulsive choice and interval timing in female rats

Animal Cognition November 2018, Volume 21, Issue 6, pp 759–772 | Cite as Females in the forefront: time-based intervention effects on impulsive choice and interval timing in female rats AuthorsAuthors and affiliations Sarah L. StuebingAndrew T. MarshallAshton TriplettKimberly Kirkpatrick Open Access Original Paper First Online: 14 August 2018 9 Shares 362 Downloads Abstract Impulsive choice has been implicated in substance abuse, gambling, obesity, and other maladaptive behaviors. Deficits in interval timing may increase impulsive choices, and therefore, could serve as an avenue through which suboptimal impulsive choices can be moderated. Temporal interventions have successfully attenuated impulsive choices in male rats, but the efficacy of a temporal intervention has yet to be assessed in female rats. As such, this experiment examined timing and choice behavior in female rats, and evaluated the ability of a temporal intervention to mitigate impulsive choice behavior. The temporal intervention administered in this study was successful in reducing impulsive choices compared to a control group. Results of a temporal bisection task indicated that the temporal intervention increased long responses at the shorter durations. Further, results from the peak trials within the choice task combined with the progressive interval task suggest that the intervention increased sensitivity to delay and enhanced timing confidence. Overall, these results indicate that a temporal intervention can be a successful avenue for reducing impulsive choice behavior in female rats, and could contribute to the development of behavioral interventions to prevent impulsive choice and maladaptive behaviors that can be applied to both sexes. KeywordsImpulsive choice Female rats Interval timing Temporal intervention  Electronic supplementary material The online version of this article ( https://doi.org/10.1007/s10071-018-1208-9) contains supplementary material, which is available to authorized users. Introduction Impulsive choice behavior entails placing a higher value on smaller sooner (SS) rewards than on larger later (LL) rewards, particularly when LL rewards provide greater reward earning over time (Mazur 1987). Within impulsive choice paradigms, choosing the SS can be viewed as a failure of self-control. In humans, a tendency towards making impulsive choices has been associated with several maladaptive behaviors, including substance abuse (e.g., Perry et al. 2005), gambling (e.g., Reynolds 2006), and obesity (e.g., Bruce et al. 2011; Weller et al. 2008), leading to the suggestion that impulsive choice is a trans-disease process (Bickel et al. 2012; Bickel and Mueller 2009). Choice behavior is an individual difference variable that remains relatively constant over time, suggesting that impulsive choice may be a trait variable in humans (Jimura et al. 2011; Kirby 2009; Odum 2011) and rats (Galtress et al. 2012; Marshall et al. 2014; Peterson et al. 2015). Past research has focused on several psychological mechanisms that contribute to individual differences in impulsive choice behavior, including individual differences in interval timing and delay aversion (Baumann and Odum 2012; Kim and Zauberman 2009; Marshall et al. 2014; McClure et al. 2014). Marshall et al. (2014) found that impulsive rats demonstrated poor time discrimination relative to non-impulsive individuals (see also McClure et al. 2014) and that impulsive rats were less tolerant of longer delays. These results indicate that poor time discrimination, delay tolerance, and impulsive choice are interrelated, and suggest that mechanisms within the core timing system may be important targets for understanding the origins of impulsive choice. Given the established relationship between these factors, time-based interventions have been developed with the goal of moderating impulsive choice. Interventions used in humans have promoted self-control using an interval fading technique within the choice task, in which LL delays were gradually increased over time (or the SS delay gradually decreased; Binder et al. 2000; Dixon et al. 1998, 2003; Dixon and Holcomb 2000; Mazur and Logue 1978; Neef et al. 2001; Schweitzer and Sulzer-Azaroff 1995). Similar findings have been discovered in male rats. Specifically, exposure to long delays prior to choice testing promoted self-control (Stein et al. 2013, 2015) and these effects persisted over a period of 4 months (Renda and Madden 2016). In addition, Smith et al. (2015) exposed rats to fixed- or variable-interval schedules on the SS and LL levers and found increased self-control, which was accompanied by improved time discrimination. These findings were subsequently replicated in experienced, middle-aged male rats (Peterson and Kirkpatrick 2016), indicating that impulsive choice can be moderated even after previous experiences with different choice tasks. Together, these results suggest that targeting timing proce (...truncated)


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Sarah L. Stuebing, Andrew T. Marshall, Ashton Triplett, Kimberly Kirkpatrick. Females in the forefront: time-based intervention effects on impulsive choice and interval timing in female rats, Animal Cognition, 2018, pp. 759-772, Volume 21, Issue 6, DOI: 10.1007/s10071-018-1208-9