Extended Data Fig. 5: Putative chromatic recurrent circuits in the medulla between Tm cells and local interneurons.
From: Hue selectivity from recurrent circuitry in Drosophila
Our EM reconstructions revealed the presence of three types of interneurons that establish synaptic recurrence between different Tms. (a,b) The medulla tangential neuron Sm3133, ramifying across medulla layers M6 and M8, was found as both pre and postsynaptic to Tm5a and Tm20. Loose reconstruction of inputs and outputs from five of these cells confirmed Tm5a and Tm20 connectivity and showed that this cell type is also pre and post synaptic to Tm5b cells. Somas are located in the medial-anterior side of the medulla. Neurotransmitter prediction suggests they are GABAergic. (c,d) Tm5a, Tm5b and Tm5c send outputs to a putatively GABAergic large tangential neuron, Sm4033 (also named CB384118), that expand its dendritic tree across medulla M6 layer and sends outputs to Tm5a and Tm5b. (e,f) Combining our Tm reconstructions and the seven column EM dataset4 we observed that Mi3 is both pre and postsynaptic to Tm5a, Tm5b, Tm5c and Tm20. (b,d,f) Single cell skeletons of Sm31, Sm40 and Mi3 (Flywire segments ids 720575940644160968, 720575940625550823, 720575940623904136 respectively).
