CaM kinase II and visual input modulate memory formation in the neuronal circuit controlling courtship conditioning

In Drosophila, calcium/calmodulin-dependent protein kinase II (CaM kinase) has been shown to be important in the expression of both learning and memory for the associative behavior courtship conditioning. In this study we examine the role of visual input in producing this behavior and the effects of modifying visual input on CaM kinase-dependent memory formation. Inhibition of CaM kinase blocked apparent learning regardless of visual input. Visual input selectively affected the memory phase of courtship conditioning: normal visual input masked the memory effects of inhibition of CaM kinase resulting in generation of memory without apparent learning, whereas disruption of visual input revealed the CaM kinase-dependence of memory. Visual input was found to be important only during the training period, which implies that vision and CaM kinase are interacting in the formation rather than the retrieval of memory. Our results suggest a model for courtship conditioning in which multiple sensory inputs are integrated at a CaM-kinase-dependent neuronal switch to modulate courtship behavior.