Interneuron Diversity: Toward a Better Understanding of Interneuron Development In the Olfactory System

Abstract

The Drosophila olfactory system is an attractive model for exploring the wiring logic of complex neural circuits. Remarkably, olfactory local interneurons exhibit high diversity and variability in their morphologies and intrinsic properties. Although olfactory sensory and projection neurons have been extensively studied of development and wiring; the development, mechanisms for establishing diversity, and integration of olfactory local interneurons into the developing circuit remain largely undescribed. In this review, we discuss some challenges and recent advances in the study of Drosophila olfactory interneurons.

Development of the mammalian main olfactory bulb

“…We do not aim for comprehensive coverage of the myriad genetic and molecular factors involved in OB development; instead, we have highlighted particular genes or proteins where they are the only known molecular contributors to particular processes, or where they appear to be especially important or interesting. Moreover, while acknowledging the huge importance of studying olfactory development in diverse model organisms ( Melkman and Sengupta, 2004 ; Miyasaka et al, 2013 ; Yang et al, 2019 ), as well as the wealth of interesting work on alternative olfactory pathways ( Katreddi and Forni, 2021 ), we focus here on the maturation of the main mammalian OB. In practice, this equates to discussing almost exclusively rodent studies and, unless specifically stated, all work described below has been undertaken in mice or rats.…”

Drosophila olfaction: past, present and future

“…and PNs (study of LNs is still in its infancy [124,125]). The reproducible one-to-one matching in the antennal lobe of the ∼50 distinct classes of OSNs and PNs that are born at different times, in different places and in distinct ways during development is an incredible example of biological precision.…”

“…Visualization of individual olfactory circuit elements reinvigorated historical interest (e.g. [122,123]) in olfactory system development, notably the specification and wiring of OSNs and PNs (study of LNs is still in its infancy [124,125]). The reproducible one-to-one matching in the antennal lobe of the ∼50 distinct classes of OSNs and PNs that are born at different times, in different places and in distinct ways during development is an incredible example of biological precision.…”

Evolutionary neuroecology of olfactory‐mediated sexual communication and host specialization in Drosophila – a review

“…In both invertebrates and vertebrates, each glomerulus is innervated by a group of OSNs that express the same chemoreceptor(s) (i.e., OSNs with identical odor response profiles) (Mombaerts et al, 1996; Gao et al, 2000; Vosshall et al, 2000). The glomeruli are connected by a network of local interneurons (LNs), which represent an early processing step for shaping the efferent olfactory information into the higher brain centers [reviewed in Grabe & Sachse (2018) and Yang et al (2019)]. The LNs’ arborization patterns diversify their anatomical structure, with some LNs innervating only a few glomeruli (so‐called patchy LNs) and others targeting many, if not all, glomeruli (so‐called panglomerular LNs) (Chou et al, 2010; Seki et al, 2010; Liou et al, 2018; Mohamed et al, 2019).…”