Digital Drosophila Archive
62 lines
3.6 KiB
Markdown
62 lines
3.6 KiB
Markdown
# Phase 4AC — upstream LIF semantics audit
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Goal context: usable stimulus-specific associative learning remains unachieved.
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This stage is a prerequisite diagnosis, never a substitute for that goal.
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All raw, base CSR, old models/experiments and signs remain read-only. No eta,
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threshold, gain, mask or APL calibration is changed. No conditioning, games,
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decoder, visual stimulation, or new formal runtime is produced.
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## New evidence and hypotheses
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The official Shiu paper links philshiu/Drosophila_brain_model. Commit
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91bdd1e7dcf193f3e7ca5a8933497fcef63b7960 (2024-09-14) model.py explicitly resets g
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on a spike, declares both v and g `(unless refractory)`, uses linear integration
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and strict `v > v_th`, and removes refractory time on Poisson-target neurons.
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Current frozen Phase 4B/P instead retains g, decays/accepts arrivals during
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refractory, uses explicit Euler, `>=`, and force requests respecting refractory.
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The Phase 4B config documents its refractory-g policy, so this is a documented
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adaptation difference, NOT evidence that deterministic CUDA regressed its oracle.
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Neither implementation is automatically a more accurate MaleCNS physiology model.
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## Scope of work allowed without replacing frozen brain dynamics
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1. Preserve official code/license at a pinned commit, with hashes; do not execute
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downloaded code. Extract exact source statements into an evidence table.
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2. Synthetic one-cell mathematical fixtures compare the frozen g policy with
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reset-only, refractory-only, and combined component ablations. Other arithmetic
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stays frozen. These are NOT a Brian2 reproduction (integration and scheduling
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also differ), and are not deployed to the MaleCNS brain.
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3. Simulate only the UNCHANGED frozen dynamics on actual induced 2/3/5-neuron
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circuits selected from the already observed Phase 4Z path. One force request at
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t=0, then no input, for 1,000 ms. Include no-input and real-edge feedforward
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controls. Missing external network inhibition/feedback is explicitly excluded;
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a sustained isolated response is not proof of whole-brain necessity.
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4. Validate every frozen CPU small-circuit event/state against the unchanged CUDA
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kernel, using exact float32 ordered accumulation and delay=18 steps.
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5. Recheck the five archived deterministic reference trials and all old hashes.
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All single-cell amplitudes derive from the complete unique contact-count set in
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the selected real subgraph, plus a one-contact unit fixture. Do not choose a
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successful amplitude after observing outcomes. Add a refractory-arrival fixture
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at t=0/1/2/2.2/2.3 ms and a sustained-input-then-off fixture (100 ms then100 ms).
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These describe operator consequences, not measured cell physiology or tuning.
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The full learning gate still requires >=5 training seeds, independent evaluation,
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A-vs-neutral-B specificity in MBON/downstream, appropriate controls, acquisition,
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reversal, retention and delayed-reward tests. Existing transfer PASS is not that.
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## Next-stage authorization boundary
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Testing alternative semantics or measured local physiology on the full MaleCNS
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network would be a NEW model experiment, not an exact runtime optimization.
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User confirmation is requested separately. This stage does not silently execute
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or promote that experiment, even if synthetic ablations reduce firing.
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## Caveats to record
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W_syn=0.275 is the original paper's free parameter selected on its feeding circuit,
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not a universal measured MaleCNS contact efficacy. g reset by itself does not make
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the model equivalent to the author's Brian2 implementation. Old reference PASS
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means consistency with our old oracle, not matching the original author software.
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