Morphological Development of Uniglomerular Projection Neurons in the Olfactory Lobe of the Moth, Manduca sexta

Abstract

The moth Manduca sexta has been a common model for the study of the insect olfactory systems. The neuronal architecture in the antennal lobes (ALs) of insects and in the olfactory lobes of vertebrates is similar in structure and development. In Manduca, as in other olfactory systems, sensory receptor neurons send axons into the AL where they form synapses with local interneurons (LNs) and projection neurons (PNs) within the structural units of glomeruli. Here, I present the morphological development of one type of interneuron, the uniglomerular projection neuron (uPN), in normal AL development and in AL development in the absence of olfactory receptor neurons (ORNs). Using fluorescent-dye labeling of uPNs and confocal microscopy, my results show that in the absence of ORNs, uPN dendritic arborization is uncharacteristic of that in normally developing ALs, reinforcing the concept that afferent input guides the development of architecture in sensory areas of the brain.