Development‐based compartmentalization of the Drosophila central brain

Abstract

The neuropile of the Drosophila brain is subdivided into anatomically discrete compartments. Compartments are rich in terminal neurite branching and synapses; they are the neuropile domains in which signal processing takes place. Compartment boundaries are defined by more or less dense layers of glial cells, as well as long neurite fascicles. These fascicles are formed during the larval period when the approximately 100 neuronal lineages that constitute the Drosophila central brain differentiate. Each lineage forms an axon tract with a characteristic trajectory in the neuropile; groups of spatially related tracts congregate into the brain fascicles that can be followed from the larva throughout metamorphosis into the adult stage. In this paper we provide a map of the adult brain compartments and the relevant fascicles defining compartmental boundaries. We have identified the neuronal lineages contributing to each fascicle, which allowed us to directly compare compartments of the larval and adult brain. Most adult compartments can be recognized already in the early larval brain where they form a “protomap” of the later adult compartments. Our analysis highlights the morphogenetic changes shaping the Drosophila brain; the data will be important for studies that link early acting genetic mechanisms to the adult neuronal structures and circuits controlled by these mechanisms.

ATM kinase inhibition in glial cells activates the innate immune response and causes neurodegeneration inDrosophila

“…4 C and F). GFP expression was most prominent in the outer area of the optic lobe and the region where the optic lobe juxtaposes the central brain neuropil, regions that are highly populated by neuron cell bodies (26,27). Similar results were observed for other AMP transgenic reporter lines (Cecropin A1::GFP, Defensin::GFP, Drosomycin::GFP, Metchnikowin:: GFP, and Drosocin::GFP; Fig.…”

“…Neurons in the adult Drosophila brain have cell bodies at the periphery and neurites that extend internally to form the synaptic neuropil (26,27). After 7 d at 25°C, scattered, small holes were observed in the neuropil of ATM 8 /+ and ATM 8 flies but not WT flies (Fig.…”

DrosophilaCentral Nervous System Glia

“…Cortex glia (see below) remain in the cortex and associate closely with neuronal cell bodies and neuroblasts. Both of these cell types appear critical for proper CNS morphogenesis (Dumstrei et al 2003;Pereanu et al 2010). For instance, expression of a dominant negative Drosophila melanogaster epithelial (DE) -cadherin in cortex glia led to misplacement of neuroblasts and neuronal cell bodies, which in turn altered fiber tract morphology (Dumstrei et al 2003); and ablation neuropil-associated glia, including ensheathing glia led to defects in the formation of axon tracts and alterations of their trajectories (Spindler et al 2009).…”

<i>Drosophila</i> as a Developmental Paradigm of Regressive Brain Evolution: Proof of Principle in the Visual System

“…A basic organizational feature of metazoan brains is the subdivision into compartments. In the invertebrate brain, compartments are characterized by a center filled with terminal neurites (axons and dendrites) and their connections (synapses) surrounded by a network of neurite connections with interspersed long fibers and glia cells [Pereanu et al, 2010], forming a septum. Invertebrate brain compartments are further characterized by functional specificity of compartments and their afferent connections.…”

“…In Drosophila, compartments of the brain are already established during late embryonic development. Pereanu et al [2010] recognize 10 compartments in the central brain of the first instar larva, which include the antennal lobes [Oland et al, 1990], the mushroom body [Jefferis et al, 2002], and the central complex [Renn et al, 1999]. The larval brain compart- Zacharias et al [1993], and Seidel and Bicker [2002].…”