Modeling Parkinson disease in animals has been very hard. The chemical models (6-OHDA and MPTP) are good to study cell replacement therapies, but not so great for pathogenesis. And the genetic models have failed to give the mouse something like true Parkinson disease — there may be alpha-synuclein aggregates or structures akin to Lewy bodies, but no cell death, or vice versa. To add to the debate, Silke Nuber and her colleagues just published in J. Neurosci. a conditional model of Parkinson in which alpha-synuclein expression can be switched off by feeding the animals doxycyclin. This is an image from the paper, showing the expression of the transgene in the two divisions of the substantia nigra of the mice.