A toxic Alzheimer's protein spreads rapidly within the brain through the extracellular space around neurons. The protein jumps neurons, according to US scientists at the Columbia University Medical Center.

By understanding the spread of the toxic protein,tau, scientists can realize why it affects just one part of the brain in the early stages, while later, multiple areas become affected. Hence, researchers can understand how tau spreads through neurons, leading to Alzheimer's disease as well as dementia.

Columbia researchers found the spread of tau in the brains of mice a few years ago.

"This finding has important clinical implications. When tau is released into the extracellular space, it would be much easier to target the protein with therapeutic agents, such as antibodies, than if it had remained in the neuron," Karen Duff, Ph.D., professor in the department of pathology and cell biology at the Taub Institute for Research on Alzheimer's Disease and the Aging Brain and professor of psychiatry at New York State Psychiatric Institute said.

Lead scientist Jessica Wu, Ph.D., a former post-doctoral researcher at the Taub Institute, currently at Massachusetts Institute of Technology, found how tau travels from one neuron to another, releasing toxic tau protein into extracellular space, which gets picked up by other neurons. It spreads rapidly throughout the brain.

The spread becomes more accelerative when the neurons get active. Gustavo Rodriguez, Ph.D., and Abid Hussaini, Ph.D., demonstrated the speedy spread as well as the neurodegeneration in mice brains when the neuronal activity is stimulated.

Duff suggested, "that clinical trials testing treatments that increase brain activity, such as deep brain stimulation, should be monitored carefully in people with neurodegenerative diseases."

The study was published in the journal Nature Neuroscience