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fly_banc — BANC fly brain and nerve cord (2026)

Description

The connectome of the entire central nervous system of an adult female fruit fly Drosophila melanogaster, the brain together with the ventral nerve cord (VNC, the fly's analog of the spinal cord), from the "Brain And Nerve Cord" (BANC) data set. It was reconstructed by Bates, Phelps, Kim, Yang and collaborators from serial-section transmission electron microscopy images, with automated segmentation and synapse detection followed by extensive manual proofreading. Nodes are neurons, and a directed edge $(i, j)$ indicates chemical synapses from neuron $i$ (presynaptic) to neuron $j$ (postsynaptic). This is materialization v888 of the data set, as released by the authors with the published paper.

The connections were detected with two synapse detection models, both included here: the "v3" model (synapses of at least 10 voxels), which the authors recommend for new work, and the earlier "v2" model (synapses of at least 5 voxels), which the analyses of the paper use and which finds about 14% fewer connected pairs. Autapses (synapses of a neuron onto itself) were excluded by the authors from all tables except the v2 neuron-to-neuron table of the current release, which contains them (as self-loops, 140,032 in v2_all) although its documentation says otherwise; they are kept as given. Following the authors (and the convention of FlyWire Codex), pairs of neurons are considered connected if they have at least five synapses. The networks of the current release (Harvard Dataverse version 3.0, July 2026) are:

  • v3_min5, v2_min5: only the pairs of neurons with at least five synapses: these are 1,861,418 of the 12,923,260 connected pairs (23.1 million of 40.7 million synapses) with the v3 model, and 1,562,742 of the 11,176,571 connected pairs (19.3 million of 34.4 million synapses) with the v2 model.
  • v3_all, v2_all: all connections, without threshold on the number of synapses.
  • v3_split, v2_split: all connections, split according to the compartments of the two neurons where the synapses are located (the axon, the dendrite, the primary dendrite, the primary neurite, or unknown, from the authors' split of each neuron by flow centrality), so that the same pair of neurons may be connected by several parallel edges, one per pair of compartments. For neurons truncated at the boundary of the volume, the authors set the compartment on the side facing the nervous system (axon for afferent neurons, dendrite for efferent ones).

All these networks have the same nodes: the 150,802 segments marked as proofread, leaving out those classified as glia, trachea or not a neuron (neurons without connections are isolated nodes).

The earlier versions of the Dataverse dataset, all of the same materialization v888, are included as the networks with the prefixes dv2_ (versions 2.0 and 2.1, June 2026, which share their files) and dv1_ (version 1.0, May 2026), with the same six networks each. Their neuron annotations differ from those of the current release (e.g. 74 neurons were not yet marked as proofread, so that they have 150,728 nodes, and versions 2.0 and 2.1 lack the side of most neurons); their connection tables are the same as those of the current release, except for version 1.0, whose v2 tables were later replaced: its dv1_v2_all has no autapses, and its compartment table dv1_v2_split contains only 15.9 million synapses, about half of those of the other v2 tables.

The networks have the following properties:

  • (Node) banc_id: the neuron's identifier (root ID) in materialization v888 of the BANC data set.
  • (Node) side: the side of the body of the neuron (left, right).
  • (Node) region: the part of the nervous system where the neuron is (central_brain, optic_lobe, ventral_nerve_cord); empty if not assigned.
  • (Node) flow: whether the neuron is intrinsic, afferent or efferent; empty if not assigned.
  • (Node) super_class, cell_class, cell_sub_class, cell_type: the four levels of the authors' cell type hierarchy (e.g. central_brain_intrinsic, antennal_lobe_projection_neuron, multiglomerular_projection_neuron, M_lvPNm40); empty if not assigned.
  • (Node) fafb_cell_type: the matched cell type in the FlyWire (FAFB) brain connectome (see the flywire entry); empty if not assigned.
  • (Node) hemilineage: the developmental hemilineage of the neuron; empty if not assigned.
  • (Node) nerve: the nerve through which the neuron enters or exits the nervous system; empty if not assigned.
  • (Node) neuromere: the developmental neuromere (segment) of the neuron, for neurons of the ventral nerve cord; empty if not assigned.
  • (Node) neurotransmitter: the neurotransmitter predicted for the neuron from its synapses; empty if not assigned.
  • (Node) neurotransmitter_score: the confidence of the prediction (NaN if not assigned).
  • (Node) sexually_dimorphic: whether the neuron's type is isomorphic, dimorphic or female-specific, from comparison with male connectomes; empty if not assigned.
  • (Edge) weight: the number of synapses from $i$ to $j$ (in the given compartments, in the *_split networks).
  • (Edge) pre_compartment, post_compartment (only in the *_split networks): the compartments of neurons $i$ and $j$ where the synapses are located (axon, dendrite, primary.dendrite, primary.neurite, unknown).
  • (Edge) neurotransmitter, neurotransmitter_score (only in the *_split networks): the neurotransmitter predicted for the presynaptic neuron $i$ in the compartment table, and the confidence of the prediction.
Tags
Biological Connectome Weighted Multigraph Metadata
Added
2026-10-27
Citation
  • A. S. Bates, J. S. Phelps, M. Kim, H. H. Yang et al., "Distributed control circuits across a brain-and-cord connectome." Nature 656, 957-970 (2026) 10.1038/s41586-026-10735-w Sci-Hub
Upstream URL OK
https://doi.org/10.7910/DVN/7WTH1N
Upstream license
CC BY 4.0, https://creativecommons.org/licenses/by/4.0/
Networks
Tip: click on a column header to sort the list, or hover over it for a description.
Column legend
$\left<k\right>$
Mean degree
$\sigma_k$
Standard deviation of the degrees
$\lambda_h$
Largest eigenvalue of the Hashimoto (non-backtracking) matrix
$\tau$
Random walk mixing time
$r$
Degree assortativity
$c$
Global clustering coefficient
$\oslash$
(Pseudo-) diameter
$S$
Relative size of the largest component
NPs
Node properties
EPs
Edge properties
Name Nodes Edges $\left<k\right>$ $\sigma_k$ $\lambda_h$ $\tau$ $r$ $c$ $\oslash$ $S$ Kind Mode NPs EPs gt GraphML GML csv
v3_min5 150,802 1,861,418 12.34 54.04 128.34 57.50 -0.06 0.07 14 0.96 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 6.2 MiB 12.2 MiB 12.3 MiB 10.8 MiB
v3_all 150,802 12,923,260 85.70 232.52 454.41 41.73 -0.04 0.12 8 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 28.1 MiB 65.6 MiB 63.3 MiB 52.5 MiB
v2_min5 150,802 1,562,742 10.36 45.84 119.26 96.71 -0.05 0.07 18 0.93 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 5.5 MiB 10.6 MiB 10.7 MiB 9.5 MiB
v2_all 150,802 11,176,571 74.11 206.29 426.62 42.48 -0.04 0.11 9 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 24.6 MiB 57.6 MiB 55.1 MiB 45.8 MiB
v3_split 150,802 14,900,863 98.81 270.06 454.41 45.58 -0.04 0.14 8 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight pre_compartment post_compartment neurotransmitter neurotransmitter_score 38.8 MiB 101.8 MiB 101.0 MiB 80.6 MiB
v2_split 150,802 13,661,705 90.59 268.59 424.62 45.31 -0.03 0.14 9 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight pre_compartment post_compartment neurotransmitter neurotransmitter_score 35.7 MiB 93.6 MiB 93.0 MiB 72.8 MiB
dv2_v3_min5 150,728 1,861,274 12.35 54.05 128.33 57.50 -0.06 0.07 14 0.96 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 6.1 MiB 12.2 MiB 12.3 MiB 10.8 MiB
dv2_v3_all 150,728 12,921,370 85.73 232.53 454.40 41.73 -0.04 0.12 8 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 28.1 MiB 65.5 MiB 63.2 MiB 52.5 MiB
dv2_v2_min5 150,728 1,562,628 10.37 45.85 119.26 96.71 -0.05 0.07 18 0.93 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 5.5 MiB 10.6 MiB 10.7 MiB 9.4 MiB
dv2_v2_all 150,728 11,174,952 74.14 206.30 426.61 42.48 -0.04 0.11 9 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 24.6 MiB 57.5 MiB 55.1 MiB 45.8 MiB
dv2_v3_split 150,728 14,898,760 98.85 270.07 454.40 45.58 -0.04 0.14 8 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight pre_compartment post_compartment neurotransmitter neurotransmitter_score 38.8 MiB 101.7 MiB 101.0 MiB 80.6 MiB
dv2_v2_split 150,728 13,659,884 90.63 268.61 424.61 45.32 -0.03 0.14 9 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight pre_compartment post_compartment neurotransmitter neurotransmitter_score 35.7 MiB 93.6 MiB 93.0 MiB 72.8 MiB
dv1_v3_min5 150,728 1,861,274 12.35 54.05 128.33 57.50 -0.06 0.07 14 0.96 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 6.2 MiB 12.2 MiB 12.3 MiB 10.8 MiB
dv1_v3_all 150,728 12,921,370 85.73 232.53 454.40 41.73 -0.04 0.12 8 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 28.1 MiB 65.6 MiB 63.3 MiB 52.5 MiB
dv1_v2_min5 150,728 1,486,981 9.87 45.55 117.33 65.38 -0.06 0.07 18 0.93 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 5.3 MiB 10.2 MiB 10.3 MiB 9.1 MiB
dv1_v2_all 150,728 11,034,962 73.21 206.23 424.61 41.92 -0.04 0.11 9 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight 24.4 MiB 56.8 MiB 54.3 MiB 45.2 MiB
dv1_v3_split 150,728 14,242,451 94.49 257.48 454.40 44.30 -0.04 0.14 8 0.99 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight pre_compartment post_compartment neurotransmitter neurotransmitter_score 37.2 MiB 97.7 MiB 96.9 MiB 78.2 MiB
dv1_v2_split 150,728 6,116,798 40.58 134.40 284.42 57.61 0.08 0.15 11 0.96 Directed Unipartite banc_id side region flow super_class cell_class cell_sub_class cell_type fafb_cell_type hemilineage nerve neuromere neurotransmitter sexually_dimorphic neurotransmitter_score weight pre_compartment post_compartment neurotransmitter neurotransmitter_score 17.4 MiB 43.3 MiB 42.9 MiB 35.2 MiB