Lewis rats have greater response impulsivity than Fischer rats

Abstract

Impulsivity, a tendency toward immediate action without consideration of future consequences, is associated with a wide array of problematic behaviors. Response impulsivity, a type of behaviorally-assessed impulsivity characterized by behavioral disinhibition, is also associated with health risk behaviors. Response impulsivity is distinct from choice impulsivity, which is characterized by intolerance for delay. Lewis rats have higher levels of choice impulsivity than Fischer rats (Anderson & Woolverton, 2005; Madden et al., 2008; Stein et al., 2012). However, no studies have examined whether Lewis and Fischer rats have different levels of response impulsivity. The present research examined response impulsivity in the two rat strains. Subjects were 16 male Lewis and Fischer rats. Rats’ response impulsivity was measured using the Five Choice Serial Reaction Time Task (5-CSRTT). In addition, their locomotor activity was measured in locomotor activity chambers. Lewis rats had more premature responses than Fischer rats during the 5-CSRTT assessment [F(1, 14) = 5.34, p < 0.05], indicating higher levels of response impulsivity. Locomotor activity did not differ between rat strain groups [F(1, 14) = 3.05, p = .10], suggesting that overall movement did not account for group differences in response impulsivity on the 5-CSRTT. It can be concluded from this research that Lewis rats have higher levels of response impulsivity than Fischer rats, and therefore provide a valid rat model of individual differences in impulsivity.

Rapid-response impulsivity: Definitions, measurement issues, and clinical implications.

“…These tasks include the widely employed five-choice serial reaction time (5-CSRT) task (Carli, et al, 1983; Hamilton, et al, 2014), as well as the one-choice (1-CSRT or ‘fixed-choice’) and two-choice (2-CSRT) variants (Anastasio, et al, 2011; Anastasio, et al, 2013; Cunningham, et al, 2013; Dalley, et al, 2002; Dillon, et al, 2009; Winstanley, et al, 2004a; Winstanley, et al, 2004b). These operant tasks entail a series of trials in which animals respond to a visual stimulus for delivery of a reinforcer.…”

Premature responses in the five-choice serial reaction time task reflect rodents’ temporal strategies: evidence from no-light and pharmacological challenges

“…The 5-CSRTT has been used to screen multiple pharmacological manipulations for their ability to improve or impair attention and impulsivity (Chudasama and Robbins, 2004). Finally, the 5-CSRTT has been used to screen for trait impulsivity (McNamara et al, 2010; McTighe et al, 2013; Hamilton et al, 2014), which has informed the development of many rodent models of impulsivity or impaired attention (Oliver et al, 2009; McTighe et al, 2013; Hamilton et al, 2014; Loos et al, 2014). These findings have been extended throughout cognitive neuroscience, especially at the interface of attention and impulsivity with mental illness and addiction (Grottick and Higgins, 2000; Semenova et al, 2007; Semenova, 2012; Sanchez-Roige et al, 2014; Worbe et al, 2014; Irimia et al, 2015).…”

Strain and cocaine-induced differential opioid gene expression may predispose Lewis but not Fischer rats to escalate cocaine self-administration

“…Thus, Lewis rats acquire cocaine, morphine, methamphetamine, nicotine and heroin self-administration or conditioned place preference more rapidly and/or at higher rates/doses compared with Fischer rats (Ambrosio et al, 1995; Cadoni et al, 2015; Kosten et al, 1994; Kosten et al, 1997; Kruzich and Xi, 2006a, b; Nylander et al, 1995; Picetti et al, 2012; Picetti et al, 2010). Fischer and Lewis rats differ also in their stress response (Dhabhar et al, 1993; Ergang et al, 2015) and impulsivity score (Hamilton et al, 2014; Madden et al, 2008), two features related to vulnerability to addiction. Overall, comparisons between Fischer and Lewis rats in cocaine self-administration have been carried out primarily in relatively short access self-administration paradigm (≤ 6h), rather than extended access (Freeman et al, 2009; Miguens et al, 2015; Rivera et al, 2013).…”