Extended Data Fig. 10: Around 17% of ℂ4 contacts are not accounted for by the ResNet model.
From: A multi-scale brain map derived from whole-brain volumetric reconstructions
a, Layer-1 synaptic connectivity across information-processing modules in ℂ4 could support distributed sensory computation and integration. Eight (2% of ℂ4) contacts occur between sensory cells across different modules. b, These contacts include: (i) ADE→OLL; (ii) ALM→CEPD/V; and (iii) reciprocal contacts between ASH, ADL and ADF. (i) The mechanosensitive47,48 anterior neurons OLL loop around intermediate processes, whereas the processes of ADE extend towards the OLL loop, suggesting a functional role for the more elaborate loop morphology. (ii) Both CEPD and CEPV processes loop around intermediate processes and extend flattened protrusions to meet the ALM processes, in which ALM are postsynaptic. CEPD and CEPV neurons respond to head touch49, whereas ALM neurons respond to both gentle50 and harsh51 body touch, inhibit backward locomotion52 and have been implicated in the habituation of tap response53. (iii) Nociception: ASH, ADE and ADF neurons may coordinate avoidance behaviours between the taxis and avoidance modules54. c, Layer-1 to layer-3 inter-module feed-forward synaptic connectivity in ℂ4. A total of 54 (12% of ℂ4) contacts are inter-module, originate in layer 1 and target layer-3 neurons directly. A small number of taxis and avoidance sensory neurons (ADF, ADL, ASH, URX and BAG) project to all but laterals in layer 3; this contrasts with extensive anterior sensory neuron projections that almost exclusively target (sub)lateral layer-3 interneurons and motor neurons, probably mediating rapid sensorimotor transformations. d, Layer-2 and inter-module feed-forward ℂ4 synaptic connectivity. Three contacts (1% of ℂ4) are inter-module and originate in layer 2. Notably, the layer-2 taxis AIY neurons synapse onto RIA—layer-3 anterior multi-compartment neurons. e, Inter-module synaptic feedback connectivity in ℂ4. Nine (3% of ℂ4) contacts provide inter-module feedback. Black arrows, synaptic contacts between cells in the same neighbourhood; grey arrows, synaptic contacts between layer-3 cells in different neighbourhoods; red arrows, synaptic contacts not accounted for by the ResNet model; solid arrows, feed-forward or recurrent (intra-layer) synaptic contacts; dashed arrows: feedback synaptic contacts.
