The Drosophila Larval Locomotor Circuit Provides a Model to Understand Neural Circuit Development and Function.

Iain Hunter,Richard A Baines,Aref Arzan Zarin,Bramwell Coulson

doi:10.3389/fncir.2021.684969

Abstract

It is difficult to answer important questions in neuroscience, such as: “how do neural circuits generate behaviour?,” because research is limited by the complexity and inaccessibility of the mammalian nervous system. Invertebrate model organisms offer simpler networks that are easier to manipulate. As a result, much of what we know about the development of neural circuits is derived from work in crustaceans, nematode worms and arguably most of all, the fruit fly, Drosophila melanogaster. This review aims to demonstrate the utility of the Drosophila larval locomotor network as a model circuit, to those who do not usually use the fly in their work. This utility is explored first by discussion of the relatively complete connectome associated with one identified interneuron of the locomotor circuit, A27h, and relating it to similar circuits in mammals. Next, it is developed by examining its application to study two important areas of neuroscience research: critical periods of development and interindividual variability in neural circuits. In summary, this article highlights the potential to use the larval locomotor network as a “generic” model circuit, to provide insight into mammalian circuit development and function.

Highlights

Little is known about how neural networks develop and function, and one factor that has impacted progress in this field, is the complexity and inaccessibility of the mammalian nervous system
The section of this review explores critical periods of development and variability
A combination of reconstructions based on a TEM volume (Ohyama et al, 2015) has posed connections between A27h and identified motor (Landgraf et al, 1997; Baines and Bate, 1998; Choi et al, 2004), inter (Kohsaka et al, 2014; Heckscher et al, 2015; Itakura et al, 2015; Fushiki et al, 2016; Hasegawa et al, 2016; Schneider-Mizell et al, 2016; Yoshikawa et al, 2016; Zwart et al, 2016; Burgos et al, 2018; Carreira-Rosario et al, 2018; Zarin et al, 2019), higher (Carreira-Rosario et al, 2018) and sensory neurons (Hughes and Thomas, 2007; Cheng et al, 2010; Fushiki et al, 2013; Vaadia et al, 2019)

Summary

Introduction

Little is known about how neural networks develop and function, and one factor that has impacted progress in this field, is the complexity and inaccessibility of the mammalian nervous system. Recent work shows that we can study murine and other model vertebrate nervous systems in more detail (Kiehn, 2016; Arber and Costa, 2018; Grillner and El Manira, 2020), the field lacks the power to describe the roles of individual neurons in mammalian. Research regarding neural circuit function is usually conducted in invertebrate model organisms like Cancer borealis, Homerus americanus, Caenorhabditis elegans, and Drosophila melanogaster.

Objectives

Conclusion