The fly's own navigation circuit is in the checkpoint and silent in the uniform-LIF model (measured: under wind JO-C/E and odor ORN_DM1 input, DNa02 0–8 Hz, EPG 3–13 Hz symmetric, PFL3 / hΔC ≈ 0 — PLAN.md §12 finding p). Real flies steer through wind (WPN → LNa → PFNa; Suver 2019, Okubo 2020) and odor meeting in the fan-shaped body (hΔC; Matheson 2022) against the EPG compass ring attractor (Seelig & Jayaraman 2015; Kim 2017; Turner-Evans 2017/2020; Hulse 2021), with PFL3 turning goal − heading into a DNa02 steering command (Westeinde 2024; Mussells Pires 2024). Today that decision is our decoder (surge / tumble / cast).
Route, following Lappalainen et al. 2024 (connectome-constrained model of the visual system: synapses fixed from the connectome, a few parameters per cell type fitted on a task, physiology predicted).
Deliverables
- Experiments first: recover the EPG / PEN / Δ7 ring order from the connectivity (circular ordering of the EPG↔PEN subgraph); inject a compass bump; test persistence, single-ness (Δ7), rotation under PEN drive, and whether PFNa wind + FB odor reach PFL3 / DNa02. Expected: the bump dies — that failure is the objective.
- Per-cell-type parameters (synaptic gain, τm, tonic current, threshold): type-gain tables in the
.dfb builder + SimulationOptions.TypeGains.
- Subgraph checkpoint extractor (CX + wind + olfactory + steering, ~5–10 k neurons) so the fast backend evaluates hundreds× real time.
- Fitting: CMA-ES / evolution strategies on the spiking model against quantitative targets — EPG bump persistence and rotation, hΔC & PFN wind tuning, PFL3 L−R ∝ sin(goal − heading), DNa02 asymmetry — or a differentiable rate surrogate trained by backprop and ported back.
- Validation on behaviour never fitted: ON surge / OFF cast (Álvarez-Salvado 2018; van Breugel & Dickinson 2014) in the room demo with the surge/cast decoder switched off and yaw read from DNa02 L−R.
Acceptance: only the encoders and the last motor mapping remain as adapters. Risk: the LIF with per-type gains may still not hold a bump → a neuron-model term (adaptation, conductance synapses) is next — still the connectome, with better dynamics.
Context: roadmap, PLAN.md §11 (F2) and §12 finding p.
The fly's own navigation circuit is in the checkpoint and silent in the uniform-LIF model (measured: under wind JO-C/E and odor ORN_DM1 input, DNa02 0–8 Hz, EPG 3–13 Hz symmetric, PFL3 / hΔC ≈ 0 —
PLAN.md§12 finding p). Real flies steer through wind (WPN → LNa → PFNa; Suver 2019, Okubo 2020) and odor meeting in the fan-shaped body (hΔC; Matheson 2022) against the EPG compass ring attractor (Seelig & Jayaraman 2015; Kim 2017; Turner-Evans 2017/2020; Hulse 2021), with PFL3 turning goal − heading into a DNa02 steering command (Westeinde 2024; Mussells Pires 2024). Today that decision is our decoder (surge / tumble / cast).Route, following Lappalainen et al. 2024 (connectome-constrained model of the visual system: synapses fixed from the connectome, a few parameters per cell type fitted on a task, physiology predicted).
Deliverables
.dfbbuilder +SimulationOptions.TypeGains.Acceptance: only the encoders and the last motor mapping remain as adapters. Risk: the LIF with per-type gains may still not hold a bump → a neuron-model term (adaptation, conductance synapses) is next — still the connectome, with better dynamics.
Context: roadmap,
PLAN.md§11 (F2) and §12 finding p.