[Further experiments on the conditioning and pseudoconditioning of the tarsal reflex in the drosophila (Drosophila melanogaster): effect of low intensity electric shocks].

In a recently described procedure of negative instrumental conditioning, applied to the tarsal reflex of Drosophila (Médioni and Vaysse, 1975), it was attempted to eliminate some "noise" sources superimposed on the associative conditioning effect. 1) By increasing the preliminary reiteration of the sugar stimulus (US for the tarsal reflex), the suppressive influence of "desensitization" (i.e. sensory adaptation and/or central habituation) could be minimized, at least in the first 20 trials of the training phase. 2) By lowering the intensity of the electrical shock used as an aversive reinforcer, the pseudo-conditioning rate could be substantially reduced too. However the relative weight of the pseudoconditioninq effects could not be decreased by these means: for the effectiveness of the mild shock became weaker for the "true" conditioning as well.