Neural features of recovery from CNS injury revealed by PET in human brain

Dysfunction of the brain occurring after local brain injury often improves clinically; however, the reason for this improvement has not been scientifically clarified. We used a new technique for imaging phosphoinositide turnover, carbon-11-labeled diacylglycerol-positron emission tomography, to observe the process of recovery from injury in human brain. Patients with local brain injury exhibited radioactive spots located in the association areas distant from the lesion, while normal controls did not exhibit such spots. These findings indicated one of possible features of the neural recovery from the central nervous system injury, which appears to play a role in modulation of synaptic transmission in the intact brain. Conventionally, attention has been directed primarily to areas surrounding brain injury, such as the penumbra; however, the present study suggests that initiation of reorganization of neural connections occurs in remote cortex.