Three-dimensional network of Drosophila brain hemisphere

TL;DR

This study presents a 3D structural analysis of the Drosophila brain network using synchrotron-radiation tomographic microscopy, classifying neuronal processes and highlighting the importance of unclassified structures in brain function.

Contribution

It introduces a novel 3D modeling approach for Drosophila brain networks and classifies neuronal processes based on their structures, revealing potential functional roles.

Findings

Classified neuronal tracts related to long-range projections and optic lobe structures

Unclassified neuronal processes correlate with contact distributions, indicating functional significance

Provides a quantitative framework for structural and statistical brain analysis

Abstract

The first step to understanding brain function is to determine the brain's network structure. We report a three-dimensional analysis of the brain network of the fruit fly Drosophila melanogaster by synchrotron-radiation tomographic microscopy. A skeletonized wire model of the left half of the brain network was built by tracing the three-dimensional distribution of X-ray absorption coefficients. The obtained models of neuronal processes were classified into groups on the basis of their three-dimensional structures. These classified groups correspond to neuronal tracts that send long-range projections or repeated structures of the optic lobe. The skeletonized model is also composed of neuronal processes that could not be classified into the groups. The distribution of these unclassified structures correlates with the distribution of contacts between neuronal processes. This suggests that neurons that cannot be classified into typical structures should play important roles in brain functions. The quantitative description of the brain network provides a basis for structural and statistical analyses of the Drosophila brain. The challenge is to establish a methodology for reconstructing the brain network in a higher-resolution image, leading to a comprehensive understanding of the brain structure.