Giant neuron input in mutant and wild typeDrosophila

Summary

Giant neurons of wild typeDrosophila can be driven to spike by various mechanical inputs, but not by visual inputs. In two genetically and phenotypically different mutants visual input can drive the giant neurons. This is taken as evidence that such a connection may also exist in wild typeDrosophila, at subthreshold level.

• 2. In at least one of the mutant stocks the giant neuron provides inputs to all contralateral dorsal longitudinal muscle fibers.

• 3. In mutant animals, visual input elicits spike activity in the giant neuron and flight.

• 4. Visual input to mutant giant neurons is mediated by the compound eyes, not the ocelli. Each neuron receives binocular activation.

• 5. The giant neuron responds to the onset, but not the end, of a flash of light.

• 6. An analysis of tarsal and wind receptor input to the giant neuron was carried out. Tarsal inputs are an important conjugate to wind input for eliciting giant neuron activity. The interaction of these inputs was further corroborated by showing that either can influence the latency and probability of the response of the giant neuron to the other.

• 7. The giant neuron inDrosophila and the DMD neurons of the locust are compared. Results indicate that the previously described anatomical analogy between these two systems can be extended in two ways: to a physiological input (vision), and to the behavioral function of the output (jumping).