L-DOPA Rescues Reach Height but Not Trajectory Area in a Bimanual String-Pulling Behavior in Parkinsonian Rats

In rats with unilateral 6-hydroxydopamine (6-OHDA) lesions, dopamine depletion reduces string speed, pulling bout duration, paw speed during reaching, and trajectory area, but not trajectory variability.

• Why it matters: Bradykinesia and hypokinesia are well studied in rodent Parkinson’s models, yet limb and bimanual coordination deficits are harder to quantify with rich behavioral readouts.
• What they did: The study introduced a novel bimanual string-pulling task in 6-OHDA-lesioned rats and tested levodopa (L-DOPA) effects on multiple movement metrics, including reach height and trajectory area.
• The result: L-DOPA restores paw speed, string-pulling speed, and fully restores paw reach height and pulling bout duration, but does not affect trajectory area, enabling treatment assessment of specific motor features.