TABLE 2.

Collection of Data Indicating the Survival of Grafted Neurons in the Host’s Brain

Indicator	Type of Evidence
Long-lasting improvement of motor state in “off” condition	Indirect evidence
Long-lasting reduction of the requirement of the DA drugs	Indirect evidence
PET imaging with labeled Levodopa	Indirect evidence
Correlation, PET/motor measurements	Indirect evidence
Functional improvement of movement-related brain activation (PET/MRI)	Indirect evidence
Demonstration of DA release by transplant	Indirect evidence
Postmortem examination of grafted brain	Direct evidence