Figure: Organization of the descending neurons in the central brain of Manduca sexta. A, B Schematic drawing showing the moth and location of the dye application in the neck connectives. C, D Maximum intensity projection of DNs in the central brain in anterior and posterior view. E, F Location of cell bodies in the different parts of the brain.
Neural synchronization is a feature of the nervous system and is critical for visual scene processing, olfactory mixture processing, and auditory processing. The Manduca sexta moth exhibits neural synchrony in the antennal lobe (AL), the primary olfactory system. Floral information is transduced by olfactory sensory neurons (OSNs) on the antennae to the AL. This complex odor information is processed by projection neurons associated with individual AL glomeruli, which project to the higher brain centers, including the lateral accessory lobe (LAL). This information from the brain and LAL region projects to the ventral nerve cord (VNC) that initiates the flight behavior via the descending neurons (DNs). As the first part of the project, we performed the retrograde staining of the DNs in the neck connectives. The main aim was to characterize the distribution and organization of DNs in the brain (Figure 2). Interestingly, we have identified five clusters of cell bodies in the brain. In addition, we also observed the neuronal innervations in the AL and optic lobe (Figure 3). This study forms the basis for single-neuron staining of the DNs. The neuronal architecture of these neurons is not mapped in the VNC. The neuron stained intracellularly will be reconstructed and placed in the standard brain as shown in figure 3.