Fig 2. Diffusivity measures correlated with MPTP dose.

Diffusivity ratios (dimensionless, affected side divided by normal side) correlated with MPTP dose (mg/kg body weight). The diffusivity measures include (A) Mean diffusivity (R² = 0.33, p = 0.02), (B) Radial diffusivity (R² = 0.31, p = 0.02), and (C) Axial diffusivity (R² = 0.32, p = 0.02). Crosses indicate monkeys in which there was less than 50% loss of nigral cell bodies, and circles indicate monkeys in which there was a greater than 50% loss of nigral cell bodies.