title: 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.
authors.affiliation: Department of Medical & Clinical Psychology, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA. Electronic address: khamilt4@umd.edu.
authors.forename: Kristen R
authors.initials: KR
authors.lastname: Hamilton
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, USA; Child Study Center, Yale University School of Medicine, New Haven, CT 06510, USA. Electronic address: marc.potenza@yale.edu.
authors.forename: Marc N
authors.initials: MN
authors.lastname: Potenza
authors.affiliation: Department of Medical & Clinical Psychology, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Program in Neuroscience, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA. Electronic address: neil.grunberg@usuhs.edu.
authors.forename: Neil E
authors.initials: NE
authors.lastname: Grunberg
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003216:Conditioning, Operant / Q000502:physiology; D007175:Impulsive Behavior; D008297:Male; D008960:Models, Psychological; D009043:Motor Activity / Q000502:physiology; D011916:Rats, Inbred F344 / Q000523:psychology*; D011917:Rats, Inbred Lew / Q000523:psychology*; D011930:Reaction Time / Q000502:physiology
keywords: Fischer; Five Choice Serial Reaction Time Task (5-CSRTT); Lewis; Rats; Response impulsivity