Heavy metal staining in the LC of a MND patient. (A) One LC neuron in this field stains densely with AMG, making it difficult to judge whether the neuromelanin is obscured or whether this is a non-pigmented neuron. (B) A pigmented neuron with light AMG staining, seen as more than 10 small black grains within the yellow-brown neuromelanin. (C) Three pigmented neurons with no quantifiable AMG grains (none in the two neurons on the right, and fewer than 10 grains in the neuron on the left). (D) A large non-pigmented neuron with no heavy metal staining. (E) Three small non-pigmented neurons with no heavy metal staining. No glial cells in the LC stain for heavy metals. Bar = 15 μm. AMG and hematoxylin.