A radical Parkinson's treatment that delivers a drug directly to the brain has been tested in people.
Patients in the trial were either given the drug, which is administered via a "port" in the side of the head, or a dummy treatment (placebo).
Both groups showed improved symptoms, meaning it was not clear if the drug was responsible for the benefits.
However, scans did find visual evidence of improvements to affected areas of the brain in those given the drug.
The study's authors say it hints at the possibility of "reawakening" brain cells damaged by the condition.
Other experts, though, say it is too early to know whether this finding might result in improvements in Parkinson's symptoms.
