Fig. 2.

Conserved identity of calyx glomeruli defined by projection neuron input. Expression of n-syb-GFP (green) by PN GAL4 lines GH146 (A), NP225 (B), and MZ612 (C) at presynaptic terminals in the larval calyx or AL (C Bottom). Two individuals (i and ii) are shown for each line. Confocal sections through the middle of calyces (two horizontal sections from slightly different levels) or larval antennal lobes (frontal sections) are shown. Glomeruli are visualized by using antibody to Dlg (magenta) and outlined by using dashed lines. In A and B, either green (for n-syb-GFP-positive) or magenta (for n-syb-GFP-negative) is used. In C, only n-syb-GFP-positive glomeruli are outlined, in white. In GH146, Aiii shows separate channels of Ai Upper; note the scattered spots of n-syb-GFP labeling, not in glomeruli, in the interior of the GH146 calyx. Further sections from GH146 and NP225 are shown in Fig. 5. (C) In many MZ612 calyces, a process can be seen linking L8 with A3/A4, (Ci Middle, dotted rectangular outline, green channel shown in Inset). Antennal lobes of MZ612 are each from the same brain hemisphere as the calyces shown above them. Both are innervated in a medial glomerulus (surrounded by a dashed line in the right half of each panel) by a PN that strongly expresses n-syb-GFP; its primary neurite can be seen coming from the direction of the cell body and projecting (dashed arrow in i) toward the inner antennocerebral tract. Weakly labeled AL glomeruli (dashed line in the left half of Cii) and calyx glomeruli (arrowheads in C) were sometimes also seen. Anterior (for calyces) or ventral (for antennal lobes) lies to the bottom, and medial is to the right in each panel. (Scale bars, 10 μm.)