overlaps develops from sends synaptic output to region receives synaptic input from neuron sends synaptic output to cell optic cartridge medulla photoreceptor cell R7 photoreceptor cell R8 R8 Fischbach and Dittrich (1989) suggest there may be two (non-DRA) variants of R8, one terminating in each of M3 and M4; this has not been substantiated in subsequent papers. FBbt:00004227 VFB:FBbt_00004227 fly_anatomy.ontology Inner photoreceptor cell of the ommatidium whose rhabdomere is located proximally, directly below that of R7 (Wernet and Desplan, 2004). It has a single axon that extends through a single column of the lamina without making synapses and crosses the first optic chiasm to reach the medulla (Fischbach and Dittrich, 1989). It forms reciprocal inhibitory histaminergic synapses with the R8 photoreceptor of the same optic column (Schnaitmann et al., 2018), with a large proportion in the first optic chiasm (Kind et al., 2021). It is also cholinergic (Davis et al., 2020). CL:0000709 FBbt:00003717 R8 FlyBrain_NDB:10113 FlyBrain_NDB:10114 receptor cell R8 lamina receptor cell R8 first optic chiasma inner photoreceptor cell photoreceptor R8 precursor cell adult cholinergic neuron