New radiotracer allows scientists to count synapses in people’s brains

Radiolabeled molecule could aid researchers studying the loss of synapses involved in Alzheimer’s, epilepsy, and other brain diseases

When it comes to processing information in the human brain, much of the work happens at the organ’s 100 trillion or so synapses, the gaps between neurons through which the cells communicate.

Researchers now report a way to measure the density of synapses in people using positron emission tomography, or PET. The method could help elucidate the mechanisms behind diseases in which people lose synapses, such as epilepsy, Alzheimer’s disease, and possibly depression, the scientists say.

Measuring synaptic density in living people had not been possible previously, say Sjoerd J. Finnema and Richard E. Carson of Yale University, who led the team. Scientists have instead been making such measurements in tissue collected during brain surgery or from deceased patients. Read more.