Physiological properties, time of development, and central projection are correlated in the wing mechanoreceptors of Drosophila

The wing of Drosophila contains 8 sensory structures (campaniform sensilla), which lie in specific locations and possess identical surface morphology. The axons of the campaniform neurons follow either a medial or a lateral tract within the CNS. Previous studies (Palka et al., 1986) indicate that choice of central pathway correlates with the time of birth and differentiation of the neurons rather than with their topographic distribution on the wing. On the basis of the response properties revealed by mechanical and electrical stimulation, these sensory cells also fall into 2 physiological categories, rapidly and slowly adapting, that correlate exactly with central projection and birthdate. Thus, within this discrete population of sensory neurons there exists a precise 3-way correlation between physiology, central projection, and time of development.