AP1 effects on NMJ plasticity are tightly correlated with motor neuron expression. Upper panel shows the effect of inhibition or activation of AP1 in motor neurons using two different motor-neuron GAL4 drivers, C380 and OK6. Representative EJC traces are also shown to highlight the contrasting results of AP1 inhibition or activation. The lower panel shows that similar manipulations in either non-motor neurons (ChaGAL4) or post-synaptic muscle (MHCGAL4) has minimal effects on synaptic plasticity. Dotted lines represent control levels (for actual values see Table 1). Scale bar: X-axis = 20 msec and Y-axis = 20 nA.