Ontogeny of two‐way avoidance in male and female rats

Abstract

In Experiment I, 17-, 21-, 36-, 51-, 90-, and 200-day-old male and female rats were given a single session of 100 two-way avoidance (TWA) trials. In the 2nd experiment, males and females of these ages and 15 and 28 days of age that were obtained from a different source, weaned at a later age, and housed differently received TWA training. Results of both studies showed that avoidance of 15-, 17-, and 21-day-old rats is low, but avoidance increases from 21 to 51 days of age. Avoidance of 95- and 200-day-old animals was generally lower than 51-day-old rats. No significant gender differences appeared until 90 days of age; at this age avoidance of males was lower than females. In Experiment III, CS intensity was varied and the US intensity was lower than that used in Experiment I and II. Avoidance of 21- and 90-day-old rats was higher with a more intense CS, but 21-day-olds were still lower than adults. Avoidance of 17-day-old rats was not affected by CS intensity.

Effects of restraint on open-field activity, shock avoidance learning, and gastric lesions in the rat

“…Early in the escape training session, escape latencies and errors increased for more severely stressed animals; later in the session, learning began to occur and errors and latencies decreased toward asymptote. Bauer (1978), we found that females always produced lower mean latencies than males. Females had significantly more avoidances than males (Figure 3).…”

Sex-specific positive and negative consequences of avoidance training during childhood on adult active avoidance learning in mice

“…The behavioral as well as the brain structural changes critically depend on the developmental time period in which the experience is encountered and the memory persistence is proportional to the age at the time of training (Zaharia et al, 1996; Heim and Nemeroff, 2001; Pollak, 2003; Romeo et al, 2003; Bock et al, 2005; Ruedi-Bettschen et al, 2005). With respect to the ontogeny of TWA learning the impact of different parameters (e.g., sex, type of CS, UCS intensity) was studied in rats and revealed a correlation between learning performance and age (Bauer, 1978, 1982). Most studies, which investigated the ontogeny of learning and memory, were conducted in rats (e.g., McLaughlin et al, 1975; McNamara et al, 1977; Bauer, 1978; Myslivecek and Hassmannova, 1979; Rudy et al, 1987), whereas less experimental data are available for mice (Hefner and Holmes, 2007; Ito et al, 2009; Akers et al, 2012).…”

“…The ontogeny of TWA learning has been well studied in rats (McLaughlin et al, 1975; McNamara et al, 1977; Bauer, 1978; Myslivecek and Hassmannova, 1979; Gruss et al, 2010). A previous study (Schäble et al, 2007) in female rats revealed that infants [postnatal day (PND) 17–21; same age as the infant mice in the present study] are not able to develop a successful avoidance strategy.…”

Appropriate end points for the characterization of behavioral changes in developmental toxicology.

“…Unlike the one-way avoidance task in which one compartment always serves as the safe area and the other as the danger area, in the two-way task (43,44) Adultlike learning of one-way active avoidance in rats is reached by 4 to 5 weeks postnatally (46). Two-way active avoidance fully develops at about the same age (47).…”