Three Sequential Collapses — Adult Cognitive Disease

The 2024 proof of concept — a unifying framework named Convergent Autophagic Collapse — identified the lysosome as a single point of failure where genetic, viral and oxidative triggers meet. That synthesis still holds. The lysosomal-acidification mechanism, the PANTHOS morphology and the Fischer–Nixon historical bridge all remain load-bearing.

But continued synthesis revealed something the singular framing did not capture: the disease is not one collapse. It is three sequential ones.

Phase I, in the locus coeruleus during the third decade of life, is bioenergetic — NAD⁺ depletion via PARP-1 hyperactivation. Phase II, decades later in the hippocampal bridgehead, is microglial — oligodendrocyte ferroptosis and the homeostatic-to-disease-associated transition. Phase III, in symptomatic disease, is structural — MMP-9 digestion of perineuronal nets and the loss of parvalbumin-interneuron drive.

Convergent Autophagic Collapse describes Phase II's lysosomal mechanism precisely. The tripartite architecture supplies what flanks it on either side.

The three phases

	Phase I · Age 20–50	Phase II · Age 50–70	Phase III · Age 70+
Locus	Locus coeruleus, dorsal raphe	Hippocampus, oligodendrocytes	Perineuronal nets / PV⁺ cells
Driver	NAD⁺ depletion via PARP-1	Ferroptosis + DAM transition	MMP-9 digestion of aggrecan
Drug class	PARP inhibitors (veliparib)	Ferroptosis inhibitors / GPX4	MMP-9 inhibitors (minocycline)
Whitepaper	PARP and the locus coeruleus	Oligodendrocyte ferroptosis	The MMP-9 therapeutic window

The foundational anchor (Phase II)

In 1907, Oskar Fischer argued that senile plaques were not merely extracellular deposits but miliary necroses — the debris fields of neurons that had died from the inside out. Modern ultrastructural analysis by Ralph Nixon validates that intuition: plaques are born from PANTHOS neurons ("poisonous flowers"), neurons engorged with undigested autophagic vacuoles because their lysosomes have failed to acidify. PSEN1 mutations, HSV-1 infection and HNE-mediated v-ATPase oxidation all converge on that lysosomal failure.

That mechanism is the heart of Phase II — the microglial and lysosomal stage. The 2024 framework was correct; it simply named the part for the whole.

What follows

In this revised model, the amyloid plaque is the tombstone of a Phase II neuron — but the disease began in Phase I and ends in Phase III. Removing the plaque has not cured the disease because it neither restores the upstream noradrenergic NAD⁺ pool nor rescues the downstream perineuronal-net cage that holds cortical oscillation together.

The corpus that argues each phase in full is shelved along that same timeline — Groundwork, then Phase I, II and III, then Convergence and Synthesis. The seven monographs tell it as narrative; the papers here are the evidence underneath.

Why this reading was available for a century and not taken is the subject of The Century-Long Silence.