NEGATIVE CORRELATION BETWEEN TONE (S-) AND WATER INCREASES TARGET BITING DURING S- IN RATS

Eighteen Long-Evans rats were exposed to a MULT VT 30-sec EXT schedule of water presentations. The EXT schedule was signaled by a 2500-Hz, 7 0-dB tone. Mean number of bites of a plastic target during a tone (S-) increased across sessions, whereas the mean number of target bites du ring the VT component signaled by no tone (Sf) decreased across sessio ns. Changing the multiple schedule to MULT EXT EXT produced a decrease in target bites during the tone. Reinstating the original MULT VT 30- sec EXT schedule produced an increase in number of target bites during the tone (S-). Changing the multiple schedule to VT 30-sec VT 30-sec produced a decrease in target bites during the tone. The results indic ate that target biting in rats increases in the presence of the extero ceptive tone (S-) of the MULT VT 30-sec EXT schedule, and that target biting during the tone varies directly with the negative correlation b etween tone and water presentations.