Small field neuron of the central complex with dendritic arbors in a slice (wedge) of the ellipsoid body and axonal arborizations in a glomerulus of the protocerebral bridge and in the gall (Hanesch et al., 1989; Lin et al., 2013; Wolff et al., 2015). It receives input from several types of ring neuron (Hulse et al., 2021).
Distal medullary wide-field amacrine neuron whose cell body is located in the anterior region of the cell body rind of the medulla. It branches extensively at the distal surface of the medulla forming a moderately broad arbor with each branch making a distinctive bouton-like terminal in the region between M1 and M2 (in the same sublayer as Dm18, and more proximal than Dm9 and Dm10 in M1), from which short, fine terminal branches project (Morante and Desplan, 2008; Fischbach and Dittrich, 1989). The arbor varies in shape between cells, covering around 20-30 columns, but with these areas overlapping. The size of the terminals of Dm1 is smaller than those of Dm18. There are around 40 Dm1 neurons per hemisphere. They are glutamatergic (Davis et al., 2020).
Distal medullary wide-field amacrine neuron whose cell body is located in the cell body rind of the medulla. It terminates with a small bushy arbor with mixed terminal morphology in layers M3-M6B. The arbors in M6B extend into neighboring columns on the dorsal side. The small arbors cover 2 columns in M6 and one in the other layers. It is cholinergic (Konstantinides et al., 2022).
Distal medullary wide-field amacrine neuron whose cell body is located in the cell body rind of the medulla. It projects asymmetrically along layers M2 and M3A forming mixed morphology arborizations (Morante and Desplan, 2008; Fischbach and Dittrich, 1989). The arborization is proximal to that of Dm15 in M2 and distal to Dm4, Dm12 and Dm20 in M3B. Its arbor has a distinct narrow and elongated shape, covering one column wide and 10 columns long. The arbors overlap significantly between cells, aligning with rows of medulla columns, and extending in one of two orthogonal orientations. It is a glutamatergic neuron (Raghu and Borst, 2011). There are two subtypes with different dendrite orientation, synaptic partners and gene expression (Ozel et al., 2021).
Distal medullary wide-field amacrine neuron whose cell body is located in the anterior region of the cell body rind of the medulla. The main neurite extends into M6, and then turns back to arborize in the boundary between M5 and M6, and in M3B, with mixed morphology arborizations. The arbor varies in shape between cells, covering around 21 columns, but with these areas tiling. It is located in a central position in the column, surrounded by the terminal of photoreceptors R7 and R8, with the cell boundaries following the column boundaries. There are around 40 Dm4 neurons per hemisphere. They are glutamatergic (Davis et al., 2020).
A serotonergic (Lee et al., 2011) and GABAergic (Haynes et al., 2015) mushroom body intrinsic neuron of the adult whose large cell body (~12um) is located in the dorsal posterior medial area of the brain, ventromedial to the calyx (Waddell et al., 2000; Tanaka et al., 2008). There is one of these cells per hemisphere and it innervates the entire ipsilateral mushroom body lobe system and distal pedunculus (Tanaka et al., 2008; Li et al., 2020). Its cell body fiber bifurcates in the superior neuropils, with one branch entering the tip of the gamma lobe and the other branching to enter at the base of the alpha lobe/lateral gamma lobe and the tip of the alpha’ lobe (Waddell et al., 2000; Tanaka et al., 2008). It is synapsed to and by Kenyon cells throughout the mushroom body lobes and also has outputs to dopaminergic mushroom body input neurons (DANs) and mushroom body output neurons (MBONs) (Takemura et al., 2017; Li et al., 2020). This neuron is also electrically connected to the mushroom body anterior paired lateral cell (Wu et al., 2011). It is involved in sleep and memory consolidation (Haynes et al., 2015). It is a secondary neuron (Truman et al., 2023) that develops from the DM3 neuroblast (Ito et al., 2013).
R-neuron that passes through the ellipsoid body canal, entering the neuropil from the posterior part of the canal and projecting outwards and slightly anteriorly (Omoto et al., 2018). Its terminals define the boundary between the inner and outer posterior layers of the ellipsoid body (Omoto et al., 2018). Unlike most other R-neurons, its dendritic branches are found on the lateral surface of the lateral accessory lobe, rather than the bulb (Omoto et al., 2018).
R-neuron that enters the ellipsoid body from the central canal, projects centrifugally, and has axon terminals throughout the outer central domain of the ellipsoid body (Hanesch et al., 1989; Young and Armstrong, 2010; Omoto et al., 2018). It does not arborize in a narrow region on the outermost periphery of this domain, which is where R4d terminals are found (Omoto et al., 2018). Proximal dendrites of R2 form club-shaped glomerular endings in the medial two-thirds of the superior bulb (Omoto et al., 2018).
R-neuron that has centrifugal projections into the ellipsoid body; there are several subclasses, but they all arborize more proximally than R2 and more anteriorly than R1 (Omoto et al., 2018).
R-neuron that arborizes only in the outer central domain of the ellipsoid body (Renn et al., 1999; Omoto et al., 2018). Arborizing branches enter the ellipsoid body from the periphery and extend inwards, centripetally (Hanesch et al., 1989; Omoto et al., 2018).
Intrinsic amacrine neuron of the lamina with arborizations spanning the proximal and distal lamina, whose cell body lies proximal to the lamina (Fischbach and Dittrich, 1989; Meinertzhagen and Sorra, 2001). It has extensive arborizations and forms a substantial number of presynaptic terminals with columnar neuron T1 and epithelial glia (Rivera-Alba et al., 2011). It receives strong input from each of photoreceptors R1-R6, and from lamina wide-field cells (Rivera-Alba et al., 2011). It is a glutamatergic neuron (Davis et al., 2020). There are approximately 210 of these cells on each side (Nern et al., 2025).
Unicolumnar medullary intrinsic neuron with bushy, fine arborizations in medulla layers M1, M5 and M9-10 (Fischbach and Dittrich, 1989; Kind et al., 2021). The projection of this neuron branches at the inner-face of the medulla to form two to three varicose recurrent terminal specializations that extend back up to the inner border of layer M8 (Fischbach and Dittrich, 1989; Morante and Desplan, 2008). In central (non-dorsal margin) columns it receives input from an R8 photoreceptor cell, but connections are substantially weaker in dorsal margin columns (Kind et al., 2021). Pre-synaptic terminals are present mainly in medulla layers M9-M10, but also in all other layers where neurites extend laterally (Pankova and Borst, 2017). It receives input from lamina monopolar neurons L1 and L5 and centrifugal neuron C2 (Takemura et al., 2013). It outputs to T4 neurons and transmedullary neuron Tm3a (Takemura et al., 2013). It is a cholinergic neuron (Hasegawa et al., 2011; Pankova and Borst, 2017). There is usually one of these cells per optic column (Nern et al., 2025).
Medulla intrinsic narrow field neuron with both fine and bleb-type arborizations in medulla layers M1, M2, M3 and M8, but with only fine arborizations in medulla layers M4 and M5, and only bleb-type arborizations in medulla layer M9 (Morante and Desplan, 2008; Fischbach and Dittrich, 1989). It receives input from the lamina monopolar neuron L5 and photoreceptor R8 (Takemura et al., 2013). It is a GABAergic neuron (Takemura et al., 2017). There is usually one of these cells per optic column (Nern et al., 2025).
Medulla intrinsic narrow field neuron with a bushy mix of bleb-type and fine terminal arborization in layers M2, M3 and M4 and in the lower medulla layers M9-M10 (Fischbach and Dittrich, 1989; Kind et al., 2021). It establishes pre- and post-synaptic connections in both the inner and outer medulla layers (Fischbach and Dittrich, 1989; Morante and Desplan, 2008). It receives input from lamina monopolar neuron L3 (Takemura et al., 2013). It is glutamatergic (Takemura et al., 2017). There is usually one of these cells per optic column (Nern et al., 2025).
Proximal medullary wide-field amacrine neuron that branches as it enters the proximal side of the medulla and forms broad terminal arbors, with mixed pre- and post-synaptic terminals, mainly in medulla layer M9 (Fischbach and Dittrich, 1989; Morante and Desplan, 2008).
Proximal medullary wide-field amacrine neuron that projects along M7 and branches extensively at the M7/M8 boundary with each branch projecting into medulla layer M9 where it forms an arbor with mixed bleb-type and fine terminals (Morante and Desplan, 2008; Fischbach and Dittrich, 1989).
An intrinsic columnar neuron whose cell body lies in the cortex of the medulla. The fiber of the T1 cell body branches at the medulla surface to form a T-shaped linking fiber between a bush-like arborization in the distal part of a medulla column (M1 and M2), and a bundle of climbing fibers in the equivalent column of the lamina (Fischbach and Dittrich, 1989). Synaptic connections in the lamina are exclusively postsynaptic and include a large number of connections from lamina intrinsic (amacrine) neurons (Meinertzhagen and O’Neil, 1991; Rivera-Alba et al., 2011). In the medulla, it is strongly synapsed by centrifugal neuron C3 in medulla layer M2 and lamina monopolar neuron L2 (Takemura et al., 2008; Takemura et al., 2013). There is usually one of these cells per optic column (Nern et al., 2025).
T neuron with its cell body posterior to the lobula plate and a cell body fiber that projects through the lobula plate and via the second optic chiasma, with little or no arborization, to medulla layer 10 (Fischbach and Dittrich, 1989; Shinomiya et al., 2019). It forms a fine arborization in medulla layers M9 and M10 and its axon then doubles back across the second optic chiasma to form bleb-type arborizations in a single layer of the lobula plate (Fischbach and Dittrich, 1989; Shinomiya et al., 2019). It is a cholinergic neuron (Mauss et al., 2014; Shinomiya et al., 2014). There are a large number of these cells, which are generated from neuroblasts that amplify by symmetric division (type III) before generating the T4 (and T5) neurons (Mora et al., 2018).
T4 neuron with its lobula plate arbor in layer 1 (Fischbach and Dittrich, 1989). It responds to motion in a diagonal front-to-back direction (Henning et al., 2022).
T4 neuron with its lobula plate arbor in layer 2 (Fischbach and Dittrich, 1989). It responds to motion in a diagonal back-to-front direction (Henning et al., 2022).
T4 neuron with its lobula plate arbor in layer 3 (Fischbach and Dittrich, 1989). It responds to motion in an upwards direction (Henning et al., 2022).
T4 neuron with its lobula plate arbor in layer 4 (Fischbach and Dittrich, 1989). It responds to motion in a downwards direction (Henning et al., 2022).
T neuron with its cell body in the lobula plate cell body rind and a cell body fiber that projects through the lobula plate and via the second optic chiasma, with little or no arborization, to lobula layer 1 (Fischbach and Dittrich, 1989; Shinomiya et al., 2019). It forms a fine arborization in lobula layer 1, then its axon doubles back across the second optic chiasma to form bleb-type arborizations in a single layer of the lobula plate (Fischbach and Dittrich, 1989; Shinomiya et al., 2019). It is a cholinergic neuron (Mauss et al., 2014; Shinomiya et al., 2014). There are a large number of these cells, which are generated from neuroblasts that amplify by symmetric division (type III) before generating the T5 (and T4) neurons (Mora et al., 2018).
T5 neuron with its lobula plate arbor in layer 1 (Fischbach and Dittrich, 1989). It responds to motion in a diagonal front-to-back direction (Henning et al., 2022).
T5 neuron with its lobula plate arbor in layer 2 (Fischbach and Dittrich, 1989). It responds to motion in a diagonal back-to-front direction (Henning et al., 2022).
T5 neuron with its lobula plate arbor in layer 3 (Fischbach and Dittrich, 1989). It responds to motion in an upwards direction (Henning et al., 2022).
T5 neuron with its lobula plate arbor in layer 4 (Fischbach and Dittrich, 1989). It responds to motion in a downwards direction (Henning et al., 2022).
Transmedullary narrow field neuron that terminates in lobula layer 1 with a bleb-type terminal arborization and that has fine arborizations in medulla layer M2 and bleb-type arborizations in M3 and M9 (Fischbach and Dittrich, 1989; Takemura et al., 2011). In the medulla, it receives strong synaptic input from lamina monopolar neuron L2 (Takemura et al., 2011; Takemura et al., 2013). It outputs onto T5 neurons (Shinomiya et al., 2019). It is a cholinergic neuron (Varija Raghu et al., 2011; Shinomiya et al., 2014). There is usually one of these cells per optic column (Nern et al., 2025).
Transmedullary narrow field neuron that has its main dendritic arborization in medulla layer M2 (Ting et al., 2014), where it receives input from lamina monopolar neuron L2 (Takemura et al., 2011), and additional postsynaptic terminals in M4-M5, where it receives input from lamina monopolar neuron L4 (Takemura et al., 2011). It has presynaptic terminals in layers M3, M4 and M9 (Fischbach and Dittrich, 1989; Takemura et al., 2011). Its axon follows the posterior edge of its cognate medulla column (Ting et al., 2014), then crosses the second optic chiasma to terminate in lobula layers 1 and 2 (Fischbach and Dittrich, 1989). In layer 1 it outputs to T5 neurons (Shinomiya et al., 2014). It is a cholinergic neuron (Varija Raghu et al., 2011; Gao et al., 2008; Takemura et al., 2011). There is usually one of these cells per optic column (Nern et al., 2025).
Transmedullary neuron that has dendritic arborization in medulla layers M1-M3, as well as presynaptic sites in M8 (Fischbach and Dittrich, 1989; Gao et al., 2008). In the medulla, it spans just one column (Kind et al., 2021), and receives input from lamina monopolar neuron L3 (Takemura et al., 2013) and an R8 photoreceptor (Kind et al., 2021). Its axon follows the anterior edge of its cognate medulla column (Ting et al., 2014), then crosses the second optic chiasma and projects to lobula layer 5 (Fischbach and Dittrich, 1989; Gao et al., 2008). It provides input to the lobula intrinsic neuron Li4 via many synapses (Lin et al., 2016). It is a cholinergic neuron (Gao et al., 2008). There is usually one of these cells per optic column (Nern et al., 2025).
Transmedullary narrow field neuron that terminates in lobula layers 1 and 4 with bleb-like terminal arborizations. It has fine arborizations in medulla layers M1, M4, and M5, and has bleb-type arborization in medulla layers M1, M4, M9 and M10 (Morante and Desplan, 2008; Fischbach and Dittrich, 1989). Pre-synaptic terminals are present mainly in medulla layers M9-M10, but also in all other layers where neurites extend laterally (Pankova and Borst, 2017). It receives input from lamina monopolar neuron L1 and L5 and medullary intrinsic neuron Mi1 and it outputs to T4 neurons (Takemura et al., 2013). It seems to be capable of both cholinergic (Pankova & Borst, 2017) and GABAergic (Raghu et al., 2013) neurotransmission.
Transmedullary narrow field neuron that terminates in lobula layers 1, 2 and 4 with bleb-type arborizations, and with fine arborizations in layer 3. It displays fine arborizations in medulla layers M2, M3, M4 and M9, and has bleb-type arborizations in layers M2, M4, and M9 (Morante and Desplan, 2008; Fischbach and Dittrich, 1989). In the medulla, receives input from lamina monopolar neuron L2 and centrifugal neuron C3 (Takemura et al., 2013). In lobula layer 1, it outputs to T5 neurons (Shinomiya et al., 2014). It seems to be capable of both cholinergic and GABAergic neurotransmission. There is usually one of these cells per optic column (Nern et al., 2025).
Transmedullary narrow field neuron that has most of its dendritic arborization in medulla layers M2 and M3, with some extensions into M1, M4 and M5 (Gao et al., 2008; Ting et al., 2014), and presynapses in M3 (Gao et al., 2008). Its axon follows the posterior edge of its cognate medulla column (Ting et al., 2014), then crosses in the second optic chiasma and terminates in lobula layer 1 (Fischbach and Dittrich, 1989; Ting et al., 2014), where it outputs to T5 neurons (Shinomiya et al., 2014). It is a cholinergic neuron (Gao et al., 2008; Shinomiya et al., 2014). It expresses the transcription factor sim (Ozel et al., 2021). There is usually one of these cells per optic column (Nern et al., 2025).
Transmedullary Y neuron that terminates with bleb-type arborizations in lobula layers 4 and lobula plate layer 4. It displays fine arborizations in medulla layers M1, M2, M4, M5, M6, M8, and M10, and has bleb-type arborizations in medulla layers M5 and M10. It is cholinergic (Davis et al., 2020).
Transmedullary Y wide-field neuron that terminates with both fine and bleb-type arborizations in lobula layer 4 and in lobula plate layers 2, 3 and 4, but shows only fine arborizations in lobula plate layer 1. It displays both fine and bleb-type arborizations in medulla layer M8, but has only fine arborizations in medulla layer M3 and M4 (Morante and Desplan, 2008; Fischbach and Dittrich, 1989). It is cholinergic (Konstantinides et al., 2022).
Transmedullary Y narrow field neuron that terminates with both fine and bleb-type arborizations in lobula layers 4, 5 and 6, and in lobula plate layer 3, but only has fine arborizations in lobula plate layer 1. It displays both fine and bleb-type arborizations in medulla layers M6 and M8, and has fine arborizations in medulla layers M2, M3, M4, M5 and M9 (Morante and Desplan, 2008; Fischbach and Dittrich (1989). It is glutamatergic (Davis et al., 2020).
Transmedullary Y wide-field neuron that terminates with bleb-type arborizations in lobula layers 4 and 5, and in lobula plate layers 1 and 3. It displays bleb-type arborizations in medulla layers M6 and M10, and has fine arborizations in medulla layers M1, M2, M4, M5 and M6 (Morante and Desplan, 2008; Fischbach and Dittrich, 1989). It is cholinergic (Konstantinides et al., 2022).