Non-linear effects in the retention of an avoidance task induced by anabolic steroids

The results of the study reported in Brain Research in 1995 by Isaacson et al. [Isaacson, R.L., Varner, J.A., Baars, J.-M., de Wied, D., 1995. The eff ects of pregnenolone sulfate and ethylestrenol on retention of a passive av oidance task. Brain Res. 689, 79-84] have been re-examined with special emp hasis placed on the distributions of latencies found in the passive avoidan ce task using rats. This study used two retention tests, one 24 h after tra ining the other at 48 h after training. In the first experiment in that stu dy a range of doses of two anabolic steroids, pregnenolone sulfate and ethy lestrenol, were given s.c. just after the footshock training trial. In expe riment 2 a similar range of doses of both steroids was given to the rats 1 h before the first retention test. Placing emphasis on the distributions ra ther than measures of central tendencies revealed that, in contrast to the vehicle treated animals, the anabolic steroid treated animals exhibited bim odal distributions of response latencies. These differences between control and hormone treated animals were observed in both experiments. The new inf ormation was interpreted in terms of non-linear dynamics including some asp ects of Chaos theory. (C) 2000 Elsevier Science B.V. All rights reserved.