SNCA and nervous system disorder: Retrograde transport along peripheral nerves was also discussed as a mode of neuroinvasion after intramuscular injection with 10 μg of fibrillary mouse α-synuclein into the gastrocnemius muscle in TgM83+/− mice, which developed neurologic disease with a median incubation time of ∼129 days when the sciatic nerve was intact and showed delayed and incomplete induction of disease when the sciatic nerve was transected (41).