digital-drosophila/registry/catalog-20260929/evidence/phase4z-pn-feedback-audit/REPORT.md

Phase 4Z — PN feedback and input acceptance audit

Diagnostic only. No training, no new sign hypothesis, no candidate. The two branches reproduce sealed Phase4Y reference and DPM-off conditions. Target and three ALLNs were selected from prior data; this is mechanism exploration, not heldout validation. All source fractions are positive arrival-weight accounting, not causal percentages or voltage attribution.

Late positive inputs to KC 82312

condition	source idx	body_id	type	mean fraction
DPM_fast_current_off	30	10039	VL2a_adPN	0.170584
DPM_fast_current_off	179	10198	VA7l_adPN	0.142137
DPM_fast_current_off	368	10399	PPL202	0.006085
DPM_fast_current_off	484	10522	VL2p_adPN	0.007661
DPM_fast_current_off	1644	11761	VP1d+VP4_l2PN1	0.171804
DPM_fast_current_off	6065	16610	VA7m_lPN	0.071431
DPM_fast_current_off	6842	17484	DC2_adPN	0.067442
DPM_fast_current_off	133666	527577	VA6_adPN	0.362856
frozen_reference	30	10039	VL2a_adPN	0.170718
frozen_reference	179	10198	VA7l_adPN	0.141833
frozen_reference	368	10399	PPL202	0.006249
frozen_reference	484	10522	VL2p_adPN	0.007666
frozen_reference	1644	11761	VP1d+VP4_l2PN1	0.171787
frozen_reference	6065	16610	VA7m_lPN	0.071424
frozen_reference	6842	17484	DC2_adPN	0.067502
frozen_reference	133666	527577	VA6_adPN	0.362820

Conditional single-cell replay

Other recorded arrivals and measured APL remain fixed; original force requests and refractory logic retained. This does not test whole-brain loop necessity.

neuron_idx	condition	mode	late spike range
30	DPM_fast_current_off	base	187–188
30	frozen_reference	base	187–188
179	DPM_fast_current_off	base	163–163
179	frozen_reference	base	162–164
484	DPM_fast_current_off	base	193–195
484	frozen_reference	base	193–195
1197	DPM_fast_current_off	base	228–228
1197	DPM_fast_current_off	omit_ALLN	217–218
1197	frozen_reference	base	228–228
1197	frozen_reference	omit_ALLN	217–218
1381	DPM_fast_current_off	base	227–228
1381	DPM_fast_current_off	omit_ALLN	227–228
1381	frozen_reference	base	227–228
1381	frozen_reference	omit_ALLN	227–228
1511	DPM_fast_current_off	base	228–228
1511	DPM_fast_current_off	omit_ALLN	219–221
1511	frozen_reference	base	228–228
1511	frozen_reference	omit_ALLN	219–221
1644	DPM_fast_current_off	base	217–218
1644	frozen_reference	base	217–218
6065	DPM_fast_current_off	base	164–165
6065	frozen_reference	base	164–165
6842	DPM_fast_current_off	base	170–171
6842	frozen_reference	base	170–171
82312	DPM_fast_current_off	base	60–61
82312	DPM_fast_current_off	omit_ALLN	60–61
82312	DPM_fast_current_off	omit_ALPN	0–0
82312	DPM_fast_current_off	omit_DAN	59–60
82312	DPM_fast_current_off	omit_DPM	60–61
82312	DPM_fast_current_off	omit_KC	60–61
82312	DPM_fast_current_off	omit_edge_1646095	32–33
82312	DPM_fast_current_off	omit_edge_20992891	0–0
82312	DPM_fast_current_off	omit_edge_347756	38–39
82312	DPM_fast_current_off	omit_edge_3560137	50–50
82312	DPM_fast_current_off	omit_edge_3811419	50–51
82312	DPM_fast_current_off	omit_edge_46784	33–34
82312	DPM_fast_current_off	omit_edge_749243	59–60
82312	frozen_reference	base	60–61
82312	frozen_reference	omit_ALLN	60–61
82312	frozen_reference	omit_ALPN	0–0
82312	frozen_reference	omit_DAN	59–59
82312	frozen_reference	omit_DPM	60–61
82312	frozen_reference	omit_KC	60–61
82312	frozen_reference	omit_edge_1646095	32–33
82312	frozen_reference	omit_edge_20992891	0–0
82312	frozen_reference	omit_edge_347756	37–39
82312	frozen_reference	omit_edge_3560137	49–50
82312	frozen_reference	omit_edge_3811419	50–51
82312	frozen_reference	omit_edge_46784	32–33
82312	frozen_reference	omit_edge_749243	58–60
133666	DPM_fast_current_off	base	212–214
133666	frozen_reference	base	212–214

Input acceptance

odor	requests	accepted reference	accepted off	status differences	first difference ms
0	131	75	73	8	51.8
1	186	77	77	17	57.4
2	122	54	52	12	56.3
3	95	41	39	3	85.3
4	78	31	32	6	54.3
5	215	92	91	15	41.8

Identical requests do not establish matched delivered inputs. Refusal and preexisting spikes depend on endogenous state. No forcing clamp or altered refractory rule was introduced. Ancestry edges require actual emission +18 steps <= downstream spike; greedy ranking is not a unique or sufficient causal path. Repeated neuron IDs indicate a time-supported recurrent motif, not proof it is the only sustaining loop. Frozen LIF/APL, raw graph/counts, eligibility and masks unchanged. All detailed state/event checks are in regression/.