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q-bio.NC · Neurons and Cognition

Chemical synapse direction gave no forward Granger lead in 40 freely moving C. elegans after per-neuron timing control; time-reversed Granger gave a small presynaptic lead

Question: does the direction of a chemical synapse predict which neuron leads in spontaneous whole-brain calcium activity of C. elegans, after we remove one timing value per neuron? Data: 40 freely moving NeuroPAL animals (Atanas, Kim et al. 2023; primary) and 8 animals (Dag et al. 2023; replication); Cook 2019 and Witvliet 2021 D7 and D8 chemical connectomes; the Randi 2023 optogenetic signal propagation atlas. Method: net pairwise Granger index (lag 3, 1.8 s) for each pair in each animal; mean over animals; model with a timing potential per neuron plus the chemical log-weight difference; 2,000 neuron-label permutations; plan written before the outcomes. Results: without potentials, postsynaptic neurons appeared to lead (r = -0.074). With potentials, the primary effect was zero (partial r -0.010, p = 0.40, 7,872 pairs; Witvliet -0.002 and +0.006; 18 of 40 animals positive). Behaviour removal, lag 1 or 6, unstimulated animals and the Dag animals gave the same null. The pre-specified time-reversed Granger (TRGC) check gave a small presynaptic lead: +0.046, +0.047 and +0.059 (p <= 0.001), 37 of 40 animals positive, but only +0.024 to +0.037 (p = 0.025 to 0.065) in the 8 Dag animals. Pair-level smoothness controls kept +0.039 to +0.041. Forward-Granger potentials followed trace smoothness (Spearman 0.50) and trophic level (0.33); TRGC potentials did not follow smoothness. A simulation showed that unequal noise reverses forward Granger but not TRGC, and that a slower target biases both. Atlas response direction did not agree with spontaneous lead (partial r -0.014, p = 0.30; TRGC 12 of 40 animals positive). Limitations: connectomes and atlas come from other animals; 0.6 s calcium frames; pairwise analysis without conditioning; smoothness is only a proxy for indicator kinetics, so a kinetic cause of the TRGC effect remains possible; small replication set from the same laboratory; exploratory checks were added after the planned tests.

C. elegans · connectome · chemical synapse · Granger causality · time-reversed Granger · lead-lag · whole-brain imaging · NeuroPAL · signal propagation atlas · structure-function · trophic level · calcium imaging · null result · directed functional connectivity

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References

15
  1. usesIn 40 freely moving C. elegans, gap junctions predict pairwise co-activity after controls for neurite contact, soma distance and per-neuron effects; chemical synapse weight does not sci:sha256:a250df14782a179b8bee744662c1a654f7fcf33a416f07366774b9b9bb58ab5a

    We reuse its connectome edge tables, neuron types, label rules and behaviour design, and we extend its zero-lag co-activity question to directed lead.

  2. Gap junctions predict pair co-activity in three of four C. elegans whole-brain data sets, in moving and immobilised worms; the link is weak in the Randi 2023 stimulation recordings sci:sha256:fea404fc826486791a933e7997984e6864538661c3296f9983f3c22227c76e3e

    It found that Randi 2023 recordings differ from freely moving recordings; we use this to interpret the atlas disagreement.

  3. supportsAnatomical hop count predicted response probability but not fitted response timing in the C. elegans signal propagation atlas; the kernel times repeated poorly across mirror pairs sci:sha256:fbb2992177f3a36ef3a7d7199b1f39b030e515e27731b7f2da0c400d3037159e

    It found that atlas response timing does not follow anatomy; our spontaneous-lead result agrees that timing at this frame rate gives little wiring information.

  4. supportsChemical count direction gave no clear prediction gain in 559 selected worm response pairs sci:sha256:de1b39841752948225c749f9a07d8f9f49a5ea0585c8d6f82731abfbfc71fcf6

    It found that chemical direction does not predict evoked response direction in the Randi atlas; we found that the atlas direction also does not predict spontaneous lead.

  5. usesdoi:10.1016/j.cell.2023.07.035
  6. useshttps://zenodo.org/records/19388374
  7. usesdoi:10.1016/j.cell.2023.04.023
  8. useshttps://zenodo.org/records/19414639
  9. usesdoi:10.1038/s41586-023-06683-4
  10. useshttps://github.com/francescorandi/wormneuroatlas/tree/b2e13d88b670efcb3438aeacba2ad4bd6c383933
  11. usesdoi:10.1038/s41586-019-1352-7
  12. usesdoi:10.1038/s41586-021-03778-8
  13. usesdoi:10.1016/j.neuroimage.2012.09.036

    Time-reversed Granger causality.

  14. doi:10.1109/TSP.2016.2531628

    Validity of time reversal for Granger causality tests.

  15. usesdoi:10.1098/rsos.201138

    Trophic levels of directed networks.

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