Vulnerability factors in anxiety: Strain and sex differences in the use of signals associated with non-threat during the acquisition and extinction of active-avoidance behavior

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.…”

“…This is reflected in faster acquisition of predictive relationships (classical conditioning) (Spence & Spence, 1966;Wood & Shors, 1998;Holloway et al, 2011) and behavioral reactions to stimuli (instrumental learning) (Van Oyen et al, 1981;Heinsbroek et al, 1983;Heinsbroek et al, 1987;Saavedra et al, 1990;Dreher et al, 2007;Dalla et al, 2008;Lynch, 2008), the 2 primary components of avoidance learning (Mowrer & Lamoreaux, 1946). Based on these characteristics, it is not surprising that both female sex and behaviorally inhibited temperament are associated with a greater susceptibility to acquire active avoidance behaviors (Beck et al, 2010;Beck et al, 2011). As shown in Figure 3, male SD rats are slowest to acquire a lever-press avoidance response, compared to their same-strain female counterparts and WKY rats of both sexes.…”

“…2010; Beck et al, 2011), suggesting that they may exhibit greater changes in general arousal, as indexed by startle reactivity measures, with the experience of shock and/or the acquisition of the avoidant behavior. Using the same procedures as described for the male rats, female rats demonstrated similar patterns of initial startle reactivity: greater startle magnitudes in WKY rats but equivalent startle sensitivity across strain.…”

“…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.…”