Odd-skipped labels a group of distinct neurons associated with the mushroom body and optic lobe in the adult Drosophila brain.

Olfactory processing has been intensively studied in Drosophila melanogaster. However, we still know little about the descending neural pathways from the higher order processing centers and how these connect with other neural circuits. Here we describe, in detail, the adult projections patterns that arise from a cluster of 78 neurons, defined by the expression of the Odd-skipped transcription factor. We term these neurons Odd neurons. By using expression of genetically encoded axonal and dendritic markers, we show that a subset of the Odd neurons projects dendrites into the calyx of the mushroom body (MB) and axons into the inferior protocerebrum. We exclude the possibility that the Odd neurons are part of the well-known Kenyon cells whose projections form the MB and conclude that the Odd neurons belong to a previously not described class of extrinsic MB neurons. In addition, three of the Odd neurons project into the lobula plate of the optic lobe, and two of these cells extend axons ipsi- and contralaterally in the brain. Anatomically, these cells do not resemble any previously described lobula plate tangential cells (LPTCs) in Drosophila. We show that the Odd neurons are predominantly cholinergic but also include a small number of γ-aminobutyric acid (GABA)ergic neurons. Finally, we provide evidence that the Odd neurons are a hemilineage, suggesting they are born from a defined set of neuroblasts. Our anatomical analysis hints at the possibility that subgroups of Odd neurons could be involved in olfactory and visual processing.

Levy P ，Larsen C 《-》

Drosophila larvae establish appetitive olfactory memories via mushroom body neurons of embryonic origin.

Pauls D ，Selcho M ，Gendre N ，Stocker RF ，Thum AS ... -  《-》

Metamorphosis of an identified serotonergic neuron in the Drosophila olfactory system.

Roy B ，Singh AP ，Shetty C ，Chaudhary V ，North A ，Landgraf M ，Vijayraghavan K ，Rodrigues V ... -  《Neural Development》

Presynaptic developmental plasticity allows robust sparse wiring of the Drosophila mushroom body.

In order to represent complex stimuli, principle neurons of associative learning regions receive combinatorial sensory inputs. Density of combinatorial innervation is theorized to determine the number of distinct stimuli that can be represented and distinguished from one another, with sparse innervation thought to optimize the complexity of representations in networks of limited size. How the convergence of combinatorial inputs to principle neurons of associative brain regions is established during development is unknown. Here, we explore the developmental patterning of sparse olfactory inputs to Kenyon cells of the Drosophila melanogaster mushroom body. By manipulating the ratio between pre- and post-synaptic cells, we find that postsynaptic Kenyon cells set convergence ratio: Kenyon cells produce fixed distributions of dendritic claws while presynaptic processes are plastic. Moreover, we show that sparse odor responses are preserved in mushroom bodies with reduced cellular repertoires, suggesting that developmental specification of convergence ratio allows functional robustness.

Elkahlah NA ，Rogow JA ，Ahmed M ，Clowney EJ ... -  《eLife》

Temporal patterns of broad isoform expression during the development of neuronal lineages in Drosophila.

Zhou B ，Williams DW ，Altman J ，Riddiford LM ，Truman JW ... -  《Neural Development》