A quantitative three-dimensional model of the Drosophila optic lobes

Abstract

A big step in the neurobiology of Drosophila would be to establish a standard for brain anatomy to which to relate morphological, developmental and genetic data. We propose that only an average brain and its variance would be a biologically meaningful reference and have developed an averaging procedure. Here, we present a brief outline of this method and apply it to the optic lobes of Drosophila melanogaster wild-type Canton S. Whole adult brains are stained with a fluorescent neuropil marker and scanned with the confocal microscope. The resulting three-dimensional data sets are automatically aligned into a common coordinate system and intensity averages calculated. We use effect-size maps for the fast detection of differences between averages. For morphometric analysis, neuropil structures are labelled and superimposed to give a three-dimensional probabilistic map. In the present study, the method was applied to 66 optic lobes. We found their size, shape and position to be highly conserved between animals. Similarity was even higher between left and right optic lobes of the same animal. Sex differences were more pronounced. Female optic lobes were 6% larger than those of males. This value corresponds well with the higher number of ommatidia in females. As females have their additional ommatidia dorsally and ventrally, the additional neuropil in the medulla, lobula and lobula plate, accordingly, was found preferentially at these locations. For males, additional neuropil was found only at the posterior margin of the lobula. This finding supports the notion of male-specific neural processing in the lobula as described for muscid and calliphorid flies.

Chemical neuroanatomy of the Drosophila central complex: Distribution of multiple neuropeptides in relation to neurotransmitters

“…It is produced by a hybridoma clone from a library against Drosophila head homogenates (Hofbauer et al, 2009). The nc82 antibody detects the protein Bruchpilot, a component of the presynaptic active zone, and is used to label synaptic neuropil (Rein et al, 1999). No labeling was detected when staining Bruchpilot null mutants (Kittel et al, 2006).…”

Neural Lineages of theDrosophilaBrain: A Three-Dimensional Digital Atlas of the Pattern of Lineage Location and Projection at the Late Larval Stage

“…Structurally defined brain compartments, visualized in a pool of samples, are "normalized" and can be assembled into a "standard brain" (Rein et al, 1999(Rein et al, , 2002. By adding neural lineages and relating them to compart- ments and other landmarks, we have increased the granularity of the model substantially.…”

The foraging gene of Drosophila melanogaster: Spatial‐expression analysis and sucrose responsiveness

“…This antibody (used in this study at 1:200) stains glia cells as shown by colocalization studies with known glia cell markers (Campbell et al, 1994;Halter et al, 1995). The neuropile marker mouse mAb nc82 (used at 1:20, a gift from A. Hofbauer) is an Ig-G produced by a hybridoma clone from a large library generated against Drosophila heads (Hofbauer, 1991;Rein et al, 1999;Wagh et al, 2006). It is widely used in confocal images of Drosophila brains, providing a structural framework for the "standard brain" (Rein et al, 1999).…”

“…The neuropile marker mouse mAb nc82 (used at 1:20, a gift from A. Hofbauer) is an Ig-G produced by a hybridoma clone from a large library generated against Drosophila heads (Hofbauer, 1991;Rein et al, 1999;Wagh et al, 2006). It is widely used in confocal images of Drosophila brains, providing a structural framework for the "standard brain" (Rein et al, 1999). It recognizes two proteins of 190 and 170 kDa in Western blots of homogenized Drosophila heads (Wagh et al, 2006).…”