| Abstract: | Conducted 3 experiments in which the shortening reflex was elicited in 46 food-sated leeches (Hirudo medicinalis) by light flashes delivered at 20-sec intervals over a 40-trial session. In Exp I, the reflex was enhanced if Ss were stored at 5-7° C rather than 20° C. Short-term (within sessions) habituation was readily observed. In Exp II, dishabituation could be produced by a single electric shock at Trial 30. However, in Exp III, the shock also enhanced responding when delivered before Trial 1 (sensitization). No long-term (between-sessions) habituation occurred over 6 consecutive days of testing in Exp I; on the contrary, responding gradually increased. It is suggested that the simplicity of these short-term processes in leeches makes them particularly suitable for electrophysiological investigations into the neural basis of habituation and sensitization. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
