Figure 6. Spatial analysis of PDF-immunoreactivity at different ZT times under LD conditions. Staining intensities were measured in nine areas of the brain (red squares in the top-left drawing of the PDF-immunoreactive neurons). The graphs show the average standardized staining indices ± s.e.m. The bottom panel shows representative immunostainings in the anterior optic commissure region at different ZT times. Note that the morphology of the neurons is slightly different due to different angles of the individual sections, but staining intensity was almost the same at the different time points. AOC, anterior optic commisure; POT, posterior optic tract; SLP, superior lateral protocerebrum; VLP, ventro-lateral protocerebrum. To draw the PDF-immunoreactive neurons, brain sections were photographed and converted into semi-tranparent pictures in Corel Photopaint. The converted images were superimposed, and background was deleted with a threshold command in Corel Photopaint. The schematic brain structures were drawn in Corel Draw, referring to Reischig and Stengl (2002).