ABSTRACT
There is a large group of disorders of the nervous system in which the primary pathological process is the progressive selective degeneration of populations of neurons. For this reason such diseases are referred to as the neurodegenera - tive disorders. The neuronal loss occurs among specific neuroanatomical systems, and does not follow patterns of vascular supply or other regional distinctions. For example, in cases of amyotrophic lateral sclerosis, anterior horn cells are lost, yet the adjacent sensory system neurons remain unaffected. On the other hand, in cases of Friedreich’s ataxia, the reverse occurs. The mechanisms responsible for the selective vulnerability of specific neuronal groups to such degeneration remains unknown, and represents an important and perplexing challenge to those who devote their research efforts to this group of diseases.
