In Parkinson's, these darkened areas of substantia nigra gradually disappear.

患有帕金森时，黑质的深色区域逐渐消失。

" Shading" is also used in talking about drawing with a pencil or painting with some sort of oil or water paint, that is a darkened area of the drawing or the painting.

“阴影”也用于谈论用铅笔绘画或用某种油或水性颜料绘画，即绘画或绘画的黑暗区域。