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EFFECTS OF TRIMETHYLTIN ON REPEATED ACQUISITION (LEARNING) IN THE RADIAL-ARM MAZE
Citation:
Bushnell, P. AND K. Angell. EFFECTS OF TRIMETHYLTIN ON REPEATED ACQUISITION (LEARNING) IN THE RADIAL-ARM MAZE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/310.
Description:
A repeated acquisition procedure for the 8-arm radial maze was evaluated with trimethyltin (TNT). en male Long-Evans rats were trained to collect a single food pellet at the end of each baited arm on each trial of a daily 12-trial test session. our of the eight arms were baited on all trials of a given session. The set of four baited arms was changed each day, thus requiring the rat to learn a new set of baited arms in each session. n trained rats, errors (entries into unbaited arms) declined from about 4 on Trial 1 to <1 on Trials 4-12 in each session: his within-session error reduction thus defined an acquisition baseline against which the effects of TNT were assessed. earning was impaired after 7 mg/kg (iv) TNT, as shown by a slower decline in within-session error frequencies in all treated rats. rrors and response latencies were elevated for 5 weeks after TNT but returned to control levels thereafter. istological examination of hippocampi showed damage to Ammon's Horn in all treated rats 18 weeks after treatment; however, no significant relationship between degree of damage and behavioral effect was observed. nalysis of errors showed that TNT more strongly impaired the rats' ability to avoid arms in the current unbaited set than those baited arms already entered on a given trial (i .e., working memory). his technique thus appears to provide a powerful tool for the analysis of effects of chemicals on learning in rats.