Deficient proactive interference of eyeblink conditioning in Wistar-Kyoto rats

Abstract

Wistar Kyoto (WKY) rats exhibit behavioral inhibition and model anxiety vulnerability. Although WKY rats exhibit faster active avoidance acquisition, simple associative learning or the influence of proactive interference (PI) has not been adequately assessed in this strain. Therefore, we assessed eyeblink conditioning and PI in WKY and outbred Sprague Dawley (SD) rats. Rats were pre-exposed to either the experimental context, the conditioned stimulus (CS), the unconditional stimulus (US), or the CS & US in an explicitly unpaired (EUP) manner, to examine latent inhibition (LI), US preexposure effect, or learned irrelevance (LIRR), respectively. Immediately following pre-exposures, rats were trained in a delay-type paradigm (500 ms CS coterminating with a 10-ms US) for one session. During training SD rats exhibited LI and inhibition from US pre-exposures without evidence of LIRR. PI was less evident in WKY rats; LI was absent in WKY rats. Even in the context of reduced PI to CS-alone and US-alone pre-exposures, LIRR was not apparent in WKY rats. The more normal acquisition rates exhibited by WKY rats, under conditions which degrade performance in SD rats, increases the overall likelihood for WKY rats to acquire defensive responses. Enhanced acquisition of defensive responses is a means by which anxiety vulnerability (e.g., behavioral inhibition) is translated to anxiety psychopathology.

Adolescent d-amphetamine treatment in a rodent model of ADHD: Pro-cognitive effects in adolescence without an impact on cocaine cue reactivity in adulthood

“…Proactive interference from a previously relevant stimulus dimension exacerbates cognitive inflexibility when individuals are required to attend to a new stimulus feature [108]. Previous work identified reduced proactive interference in WKY in an eyeblink conditioning paradigm, whereby pre-exposure to unconditioned or conditioned stimuli did not alter acquisition rate of the eyeblink response in WKY, but slowed acquisition in outbred Sprague-Dawley rats [109]. Though it is unclear to what degree proactive interference in classical conditioning generalizes to operant conditioning, weakened acquisition, memory storage, or retrieval of the initially reinforced visual strategy by WKY in the current study could plausibly lead to reduced proactive interference during subsequent testing phases, manifesting as fewer errors and an apparently faster ability to acquire new response strategies [110].…”

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

“…Delay-type acquisition of the classically conditioned eyeblink response measures a general ability to form stimulus-stimulus associations. A recent study found an overall tendency for WKY rats to acquire an eyeblink conditioned response (CR) faster than SD rats [43]. The learning differences, however, primarily reflected a reduction in proactive interference.…”

“…In general, avoidance is apparent as greater responding in comparison to yoked subjects, however arguments may be made to the stability and suitability of yoked schedules [8,26]. As rats and humans have demonstrated similar sensitivity to other manipulations in eyeblink conditioning, such as the inter-stimulus interval [49,64], and proactive interference [1,43,60], acquisition of eyeblink avoidance in rats may resemble the human data. By implication, the enhanced acquisition of avoidance in WKY rats may be similarly expressed during eyeblink conditioning.…”

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.…”

“…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.…”