Approach-avoidance conflict in preweanling rats: A developmental study

Abstract

Ten-and lfi-day-old rat pups were trained with two procedures to approach an anesthetized mother, and then were punished for approaching. Both ages of subjects exhibited increased latencies to reapproach the mother, indicating passive inhibitions, but only the older pups retreated. All but one of the younger pups eventually reached the mother within 3 min after the punishment, while only half of the older pups did so. In a second experiment examining the development of locomotor avoidance reactions, 5· to 20-day-old rats were shocked without the mother present. Fifteen-and 20-day-old rats significantly decreased their activity patterns in reaction to shock and spent significantly less time in the shock area than either of the younger aged pups. These results suggest that flight reactions are components of a rat's defensive repertoire that appear very rapidly between 10 and 15 days of age.Although information on the effects of punishment in very young organisms is limited (Walters & Grusec, 1977), we do have a certain amount of information available with respect to the behaviors of preweanling rats (younger than 20 days) in step-through and step-down passive avoidance situations (Riccio, Rohrbaugh, & Hodges, 1968;Riccio & Schulenburg, 1969). In such situations, very young rats are slower to reach a high criterion of performance than weanling or older subjects. What has not been clear is whether the results imply that young animals are slower to learn aversive responses, or whether they do learn the contingencies of punishments, but nonetheless fail to avoid because of their innate reactions to punishing events (Campbell, Riccio, & Rohrbaugh, 1971). The question is further confounded in that the data on preweanling rats have been restricted to the examination of punishment on only untrained, highly probable responses (e.g., crossing to the dark side of an alley or stepping off a platform).The limitation to untrained response assessment has been due, in part, to a paucity of adequate techniques for studying aversively controlled, as well as appetitively controlled, behaviors in preweanling subjects. However, recent evidence (e.g., Amsel, Burdette, & Letz, 1976;Kenny & Blass, 1977) indicates that very young rats can be trained to approach an anesthetized mother for dry suckling as a reward. By punishing such a learned approach response, it would now be possible to examine further the characteristics of aversive stimulation during the very early Requests for reprints should be sent to the first author, Laboratory of Comparative and Physiological Psychology, The Ohio State University, 1314Kinnear Road, Columbus, Ohio 43212. Portions of this research were supported by PHS Grant 5 T32 MH14608-02 to The Ohio State University while Joe1le Mast and Carrie-Ellen Jacobs were NRS Fellows. stages of development. Therefore, a major concern in the present investigations was to study the effects of punishment on young pups' behaviors in approachavoidance conflict situations. Also, we were interested in examining the unlearned res...

Postnatal development of the amygdala: A stereological study in rats

“…Indeed, before showing a slow linear volumetric increase until 7 months of age, the central nucleus exhibits early exponential growth between 1 and 2 weeks of age. Functional studies have shown that flight reactions are not present in 5-day-old rat pups, are still weak at 10 days of age, but are largely mature at 15 days of age (Collier et al, 1979). Freezing in response to a conditioned stimulus appears at P10 in rats (Sullivan, 2001).…”

“…Individual components of the fear response are thought to incorporate sequentially as animals mature, eventually giving rise to what are identified as mature fear behaviors (Wiedenmayer, 2009). Indeed, several studies have revealed that distinct fear behaviors emerge at different times during early postnatal life and continue to mature during late postnatal development (Blozovski and Cudennec, 1980;Bronstein and Hirsch, 1976;Chen et al, 2006;Collier et al, 1979;Foster and Burman, 2010;Hefner and Holmes, 2007;Hubbard et al, 2004;Ito et al, 2009;Kim and Richardson, 2007;Moriceau et al, 2004;Raineki et al, 2010;Rudy, 1993;Takahashi, 1992;Wiedenmayer andBarr, 1998, 2001a,b).…”

Dual Circuitry for Odor-Shock Conditioning during Infancy: Corticosterone Switches between Fear and Attraction via Amygdala

“…Predator odor-induced freezing and coincident amygdala activation can be evoked precociously by injecting CORT in sensitive-period pups (Takahashi et al, 1991;Takahashi, 1992;Weidenmayer and Barr, 2001;Moriceau et al, 2004). Third, adrenalectomizing pups can prolong the infants' unique sensitive-period learning, such as attenuated fear and inhibitory conditioning (Collier et al, 1979;Blozovski and Cudennec, 1980;Bialik et al, 1984;Myslivecek, 1997;Moriceau and Sullivan, 2004b), as well as extend the learning-induced changes of the olfactory bulb characteristic of the sensitive period (Moriceau and Sullivan, 2004b). Fourth, sensitive-period odor-shockinduced preference learning and its olfactory bulb neural correlates can be blocked by a single injection of CORT, although pups did not learn to avoid the odor (Moriceau and Sullivan, 2004b).…”

Age-differences in odor preference following an odor-illness pairing

“…Thus, when paired with odor , LiCI may serve as a punisher and fixate the approach response to odor . There is, in fact, evidence that punishment does tend to fixate the approach response to familiar nest odors and other horne environmental stimuli (Collier, Mast, Meyer, &Jacobs, 1979;Peterson, Benton, Gordon, Misanin, & Hinderliter, 1985). Collier et al (1979) found rat pups to continue to approach a darn even though they were punished for doing so, and Peterson et al .…”

“…There is, in fact, evidence that punishment does tend to fixate the approach response to familiar nest odors and other horne environmental stimuli (Collier, Mast, Meyer, &Jacobs, 1979;Peterson, Benton, Gordon, Misanin, & Hinderliter, 1985). Collier et al (1979) found rat pups to continue to approach a darn even though they were punished for doing so, and Peterson et al . (1985) reported that preweanlings persisted in running to homecage shavings located in the nonreinforced endbox in an aversively motivated spatial discrimination task.…”