Habituation of the shortening reflex in the medicinal leech.
The shortening reflex was elicited in food-sated Hirudo medicinalis by light flashes delivered at 20-s intervals over a 40-trial session. The reflex was enhanced if animals were stored at 5-7 degrees C rather than 20 degrees C. Short-term, that is, within-sessions, habituation was readily observed. Dishabituation could be produced by a single electric shock at Trial 30. However, the shock also enhanced responding when delivered before Trial 1 (sensitization). No long-term, that is, between-sessions, habituation occurred over 6 consecutive days of testing; on the contrary, responding gradually increased.
D000818:Animals; D004597:Electroshock; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D007865:Leeches / Q000502:physiology*; D010775:Photic Stimulation; D012018:Reflex / Q000502:physiology*; D013997:Time Factors