Classical and instrumental conditioning of eyeblink responses in Wistar–Kyoto and Sprague–Dawley rats

Abstract

Wistar Kyoto (WKY) rats, an animal model of anxiety vulnerability, acquire lever-press avoidance faster than outbred Sprague Dawley (SD) rats. Faster avoidance acquisition may reflect an inherent ability to acquire cue-outcome associations, response-outcome associations or both. To evaluate cue-outcome learning, acquisition of classically conditioned eyeblink response was compared in SD and WKY rats using a delay-type paradigm (500-ms conditioned stimulus (CS) coterminating with a 10-ms unconditional stimulus (US)). WKY rats demonstrated enhanced classical conditioning, with both faster acquisition and greater asymptotic performance in delaytype training than SD rats. To evaluate response-outcome learning, separate SD and WKY rats were given control over US delivery through imposition of an omission contingency into delaytype training (emitting a conditioned response (CR) prevented delivery of the US). The schedule of US delivery derived by these rats became the training regimen for a separate group of SD and WKY rats, yoked within strain. In SD rats, no differences in acquisition were detected between those given control over US delivery and those trained with the same partial reinforcement schedule. Acquisition rates of those WKY rats with control exceeded those trained with a yokedschedule of US presentation. Collectively, WKY rats exhibit enhanced classical conditioning and sensitivity to schedules of reinforcement compared to outbred SD rats. Anxiety vulnerability, in particular inhibited temperament, may be traced to active processes in the prediction and control of aversive events.

Facilitated acquisition of eyeblink conditioning in those vulnerable to anxiety disorders

“…Similar to the behaviorally inhibited personality profile, the Wistar-Kyoto rat (WKY) demonstrates inherent anxiousness, vulnerability to stress, and avoidant behaviors (Paré, 1989a,b, 1993, 1994; Redei et al, 1994; Rittenhouse et al, 2002; Servatius et al, 2008; McAuley et al, 2009; Beck et al, 2010). WKY male rats acquire eyeblink conditioning significantly faster than outbred Sprague-Dawley rats, with greater asymptotic performance and resistance to extinction (Ricart et al, 2011). …”

Fundamental interstrain differences in cortical activity between Wistar and Sprague–Dawley rats during global ischemia

“…There are striking differences in the physiological functions of the two rat strains at many levels, e.g. behavior (Rex et al, 2004;Walker et al, 2009;Valdez et al, 2011), learning and memory (Meneses et al, 2011;Ricart et al, 2011), responses to intoxication (Riley et al, 2009), general anesthesia (SillerMatula and Jilma, 2008), enzymatic activity (Saito et al, 2004;Imamura and Shimada, 2005), gene expression (Hill et al, 1996) and focal ischemic injury (Markgraf et al, 1993;Walberer et al, 2006). Both Wistar (Pulsinelli and Brierley, 1979;Sas et al, 2008;de la Tremblaye and Plamondon, 2011) and Sprague-Dawley rats (Phillis et al, 1994;Vered et al, 1994;Caragine et al, 1998;He Fig.…”

Acquisition of Active Avoidance Behavior as a Precursor to Changes in General Arousal in an Animal Model of PTSD

“…WKY rats have been touted as a model for depression and maybe this sex-specific response reflects some aspect of those characteristics (Pare & Redei, 1993). Overall, these divergent changes in arousal and vigilance are likely a bi-product of strain and sex differences in learning processes that are involved in forming predictive associations under conditions where some level of stress is involved (Wood & Shors, 1998;Ricart et al, 2011a;Ricart et al, 2011b;Beck et al, 2011). When the requirement to cope is brought to the fore, these inherent differences in learning processes can be seen both in their rate to acquire an avoidance coping response (i.e.…”

“…From a learning-diathesis approach, vulnerability for developing anxiety disorders comes from differences in acquiring associations. People selfascribed as being behaviorally inhibited, as well as the rat model of behavioral inhibition (the WKY rat), exhibit quicker acquisition of classically conditioned responses (Ricart et al, 2011b;Myers et al, 2011;Beck et al, 2011). In addition, females also exhibit enhanced susceptibility to acquire associations.…”

“…With no prior manipulations, WKY rats exhibited similar startle sensitivity measures as Sprague Dawley (SD) rats, but exhibited higher startle responsivity (see Figure 2). These temperament and reactivity characteristics are reasonable analogs of the predisposing factors for developing symptoms of anxiety disorders; therefore, we adopted the WKY rat as our anxiety vulnerability model Beck et al, 2010;Ricart et al, 2011a;Ricart et al, 2011b;Jiao et al, 2011;Beck et al, 2011). Fig.…”