Figure 6.

Mutants lacking Synapsin are defective also in nondiscriminatory relief- and punishment-learning tasks. A, Schematic of the one-odor versions of the relief- and punishment-learning tasks. The procedure is as in the two-odor version of the paradigm (Fig. 1A; see Materials and Methods), except that one odor is omitted. That is, for one-odor relief learning, the odor (BA) is presented upon the cessation of shock, while for punishment learning the odor is presented before the onset of shock. In both cases, a second experimental group receives unpaired presentations of odor and punishment. The difference in odor preference between paired- and unpaired-trained groups indicates associative memory, and is quantified as PI. B, Also in nondiscriminatory, one-odor versions of the paradigm, relief memory and punishment memory are strongly impaired in mutant flies lacking Synapsin (synapsin⁻). Other details as in Figure 1D.