Failure to produce conditioning with low-dose trimethylthiazoline or cat feces as unconditioned stimuli.

Abstract

Trimethylthiazoline (TMT), a derivative of fox feces, has been reported to fail to produce aversive conditioning as an unconditioned stimulus (UCS) when presented in large amounts (I. S. McGregor, L. Schrama, P. Ambermoon, & R. A. Dielenberg, 2002). Experiment I evaluated very low TMT levels that nonetheless produced defensive behaviors in rats during exposure. Although each level (0.01, 0.05, and 0.10 microl TMT) produced significant change in defensiveness, none resulted in significant changes the following day in the absence of TMT. Experiment 2 evaluated cat urine, cat feces, and cat fur/skin odor against a no-odor control. Urine produced no significant changes, but feces and fur/skin odors elicited virtually identical changes in defensive behaviors during exposure. When tested the next day in the absence of odor, the fur/skin odor-exposed group showed significant differences on the same behaviors as during exposure, but the feces-exposed group showed no differences on any measure. Results suggest that lack of conditioning to TMT may relate to the type of predator odor rather than the amount, predator species, or possible lack of odor components in TMT that are present in natural feces. Predator feces may also be less effective as a UCS because they are poorly predictive of the actual presence of the predator, suggesting the need for a reevaluation of UCS functions in aversive conditioning.

Acute and chronic effects of ferret odor exposure in Sprague–Dawley rats

“…Interestingly, only ferret hair, when tested independently, induced HPA axis activation (Masini et al, 2005). In that respect, this is very similar to the report that cat hair is more potent than their urine or feces at eliciting defensive responses and contextual conditioning (Blanchard et al, 2003c). Additionally, our results of weaker HPA axis activation with ferret hair (Masini et al, 2005) is also consistent with the report that cat hair is not as potent as worn cat collars (Dielenberg et al, 2004).…”

“…One curious feature of ferret odor has been our lack of evidence of contextual conditioned effects (Masini et al, 2006a), which are relatively widespread in response to cat odors (Blanchard et al, 2003c(Blanchard et al, , 2001Hubbard et al, 2004;McGregor et al, 2002;Staples et al, 2005;Staples and McGregor, 2006;Takahashi et al, 2005), and more limited in response to TMT (Endres and Fendt, 2007;Rosen, 2004). A potential explanation for the apparent lack of ferret odor-induced context conditioning may have to do with the exact experimental conditions employed in our laboratory.…”

Exposure to Urine of Canids and Felids, but not of Herbivores, Induces Defensive Behavior in Laboratory Rats

“…Although the behavioral effects of the predator urine were by and large similar, there was one major exception: the cat urine did not induce defensive behavior. This has also been demonstrated by Blanchard et al (2003b). In that study, avoidance behavior, decreased duration of contact, and increased frequency of risk assessment behavior and freezing were induced by exposure to cat feces and cat fur/skin, but not by exposure to cat urine.…”

“…This may be explained as follows. First, predator urine in general appears to be less fear-inducing than the odor of feces or skin/fur (cf., Blanchard et al, 2003b; only cat odor was tested in this study). Second, cat odor may change during domestication so that its fear-inducing properties are weakened or lost altogether.…”

Adaptive host manipulation by Toxoplasma gondii: fact or fiction?

“…In nature, an infected rat that is not averse to the scent of cat urine may spend more time in places where a cat has been, but not necessarily more time near an actual cat, which will smell of 'cat fur', and not urine. 'Cat fur' odour elicits a much stronger aversion in normal rats [9], and this aversion may be unaffected by T. gondii [4]. Furthermore, stimuli such as the sound and movement of a cat may be important additional cues that rodents use to avoid predation.…”