Three-dimensional reconstruction of second order neurons conveying information about CO2 in the Heliothine moth brain

Abstract

Moths detect CO2 on labial palps and axons from Labial palps project into a single glomerulus, the Labial palp pit organ glomerulus (LPOG). Mass-staining of the LPOG visualized the secondary pathway in the brain. These data was used for 3D reconstrucion of neurons in the paricular pathway. Based on the preparations from Ingrid Moe Dahl we performed intensification, immunostatning and rescanned for better visualixation. After the visualization,brain neuropils and the prosjection neurons of ech of the brain preparation were constructed manually using the computer software AMIRA 5.3. The prosjection neurons from the LPOG were found to project to three main tracts: the lateral antennal lobe tract, the mediolateral antennal lobe tract and  the second mediolateral antennal lobe tract. in additionm we also observed prosjection neurons in the dorsomedial antennal lobe tract. The main termination areas of the LPOG prosjection neurons are the superior protocerebrum, and the ipsi-and contralateral lateral protocerebrum. In contrast to the previous finding, we observed LPOG prosjection neurons in the mushroom body calyces, indicating some modulation by experience. In the antennal lobe, interneurons from the LPOG and the other glomeruli. The presence of LPOG prosjection pathways. Thus, the reconstructions yielded new information relevant for understanding the putative CO2 pathway.