Toluene and temporal discrimination behavior in the rat.
Fifteen rats were trained to perform a temporal discrimination between two signal durations using a standard Skinner box with two levers. When a 2-s tone signal was presented, rats were required to press one lever ("SHORT" response), and when an 8-s tone signal was presented, they were required to press another lever ("LONG" response). Then five intermediate tone signals were introduced and all signals were pseudorandomly presented. In the case of 2- and 8-s signals, rats could gain a food reward if they pressed the correct lever. When five intermediate signals were presented, neither response was reinforced. After stable performance was established, percentages of "LONG" responses to the seven signals were calculated. The percentages increased as a function of signal durations. Then three dosages of toluene were intraperitoneally administered. Treatment with 100 mg/kg toluene increased the gradient of the psychophysical function between signal durations and percentages of "LONG" responses, and accuracy of performance improved. There was no clear change in the rats injected with 200 mg/kg. However, 400 mg/kg toluene decreased the gradient. The temporal gradient reflects discriminability of signal durations. Therefore, it was proposed that treatment with 100 mg/kg toluene improved discriminability and enhanced accuracy of temporal discrimination in the rats. The treatment with 400 mg/kg toluene reduced the accuracy of temporal discrimination.
Wada
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Hokkaido University, College of Medical Technology, Sapporo, Japan. hiromi@cme.hokudai.ac.jp
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004193:Discrimination Learning / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D008297:Male; D011601:Psychophysics; D051381:Rats; D017208:Rats, Wistar; D012055:Reinforcement Schedule; D013998:Time Perception / Q000187:drug effects*; D014050:Toluene / Q000008:administration & dosage / Q000633:toxicity*
D014050:Toluene