Fig. 6.

Intraaxonal progression of Lewy pathology in Lewy-prone systems. αS pathology is initiated at distal axons and spreads toward neuronal cell bodies in each Lewy-prone system as indicated by orange arrow, respectively. This axonal spread is in parallel with the direction of the so-called the “upward spread” (broken and empty arrow containing “?”) up to LC. However, the direction of this axonal spread is “downward” above LC. Additional projections form SN to LC (gray interrupted line) and that from LC to dmX (gray interrupted line) may be one of the candidate structures that may mediate transneuronal spread from dmX to LC (small arrow in orange) and that from LC to SN (arrowhead in orange), while these have not yet been documented in human brains with LB disease. DA dopamine, NA noradrenalin, IV forth ventricle, AC acetylcholine, SG sympathetic ganglia, IML intermediolateral nucleus