The depigmentation of neurons in the substantia nigra is a hallmark of which disease?

The depigmentation of neurons in the substantia nigra is a distinctive feature associated with Parkinson's disease. In this condition, there is a significant loss of dopaminergic neurons in the substantia nigra pars compacta, which leads to a reduction in the production of dopamine. This reduction can result in motor symptoms such as tremors, rigidity, and bradykinesia, which are hallmarks of the disease.

The substantia nigra is a key structure in the basal ganglia, which plays an essential role in the regulation of movement. The loss of pigmented neurons is due to neurodegeneration and contributes to the characteristic motor dysfunction seen in patients with Parkinson's disease. This degeneration is a direct consequence of pathological processes such as the accumulation of Lewy bodies, which contain abnormal aggregates of alpha-synuclein protein.

Other conditions listed, such as Huntington's disease, Alzheimer's disease, and spinal muscular atrophy, involve different mechanisms and brain regions. Huntington's disease primarily affects the striatum leading to movements disorders but does not specifically involve the substantia nigra in the same manner. Alzheimer's disease involves widespread neurodegeneration especially in the cortex and specific structures such as the hippocampus, without the focused depigmentation of