where 𝐼𝐶 " is the intensity change at zero levodopa concentration, 𝐼𝐶 #$% is the maximum intensity change, 𝐾 & is the concentration at half maximum intensity change and [𝐿𝐷] is the levodopa concentration. The data sets were fitted to Equation (3) with the Python function scipy.optimize.curve_fit. Based on the square root of the covariance matrices, the errors of the fit parameters were estimated.