Fig. 3.

The combined AAV/PFF injection induces more profound motor impairments than AAV-α-syn or PFFs alone, as observed in the amphetamine rotation (A), cylinder (B), and stepping (C) tests. In the experiments summarized here (compiled from [13] and [18], combined with unpublished data), the AAV/PFF treated rats developed significant impairments in all three tests already at 4 weeks post-op, and this level of impairment was maintained, or increased, at longer timepoints. In the PFF only and AAV-α-syn only groups the impairment did not exceed the limits for significant functional impairment in either the amphetamine test (set at > 3 turns/min) or in the stepping test (60% of intact side), even at the longest timepoints. In panel D, the plots give the magnitude of TH+cell loss in the individual rats in the mixed AAV/PFF group. The red dots indicate rats showing significant impairment in either of the three tests (panel Dⁱ-Dⁱⁱⁱ), or impairments in the rotation test and/or cylinder tests combined (panel D^iv), or the rotation and/or stepping tests combined (panel D^v). As discussed in the text, this points to the possibility to use scores from a combination of two tests as a screening tool to predict the magnitude of TH+cell loss that will develop long-term in the AAV/PFF treated animals.