Ellipsoid body neurons in the fly brain

This figure was compiled from image stacks (confocal microscope sections) of the Drosophila brain. Even though it is relatively small (100,000 neurons) the fly brain is highly complex and organised. The many genetic tools available for fly research makes it an ideal model organism for studying brain development, genes, learning, memory and neurodegeneration.

 

The ellipsoid body (EB) is part of the central complex neuropil in the Drosophila brain and is thought to be involved in locomotor control. The clusters of isomorphic neuron sets (R neurons) converge to form a stunning multi-layered ring structure or 'doughnut'.

 

R1-R4 neurons. A, oblique view of a c232;UAS-mCD8::GFP brain showing expression in
R3 and R4d neurons. Two clusters of perikarya can be observed (arrows).

B, coronal projections of
c232;UAS-nSyb::GFP showing presynaptic localisation in the EB ring.

C, coronal view of EB1;UASmCD8::
GFP showing expression in the R2 neurons.

D, coronal view of presynaptic localisation in the
R2 neurons of the EB in EB1; UAS-nSyb::GFP individuals is found in the outer EB ring (arrow).

E-G,
horizontal sections, anterior to the top of the image. E, horizontal view of EB1; UAS-nSyb::GFP
individuals (single confocal section). The R2 neurons project along the anterior face of the EB
(arrow), then enter the EB canal. From the centre of the EB they radiate outwards (asterisk*)
arborising in the distal EB.

F, single horizontal section slightly dorsal to E showing the arborisations
of the R2 neurons (arrow) and some GFP in the LTRs (asterisk*).

G, schematic of R2 neurons
innervating the EB in the horizontal plane.

H, coronal view of a
hsflp;c465;UAS>rCD2,y+>mCD8::GFP brain showing two R2 neurons (arrows) innervating the EB.

All images are projections unless otherwise stated. All scale bars 25μm unless other wise stated.