COMPARATIVE-STUDY OF BEHAVIORAL-DEVELOPMENT BETWEEN HIGH AND LOW SHUTTLEBOX AVOIDANCE RATS

Previously, we reported that high-and low-avoidance animals (HAA and L AA, respectively), selectively bred for different avoidance response r ates in a shuttlebox avoidance test, showed additional behavioral diff erences in wheel cage activity and in water maze performance after wea ning. In the present study, physical and behavioral development were e xamined in HAA and LAA during the preweaning period. As compared to HA A, LAA offspring showed lower body weight, delayed eye opening, poorer performance in pivoting and negative geotaxis, and increased open-fie ld activity. A fostering study indicated that these differences observ ed in eye opening, pivoting, negative geotaxis, open-field activity, s wimming speed, shuttlebox avoidance and wheel cage activity were indep endent of maternal care. Only the pup weight was strongly dependent on the maternal line. These results indicate that behavioral differences between HAA and LAA observed in the pre-and postweaning periods may b e linked to the avoidance genotype, but the difference in pup weight m ay be caused by maternal care. (C) 1998 Elsevier Science Inc.