This finding means that it may one day be possible to grow new cells to replace ones damaged by disease or spinal cord injury, such as the one that paralyzed the late actor Christopher Reeve.
"Knowing that neurons are able to grow in the adult brain gives us a chance to enhance the process and explore under what conditions -- genetic, sensory or other -- we can make that happen," said study co-author Elly Nedivi, the Fred and Carole Middleton Assistant Professor of Neurobiology.
While scientists have focused mostly on trying to regenerate the long axons damaged in spinal cord injuries, the new finding suggests targeting a different part of the cell: the dendrite. A dendrite, from the Greek word for tree, is a branched projection of a nerve cell that conducts electrical stimulation to the cell body.
"We do see relatively large-scale growth" in the dendrites, Nedivi said. "Maybe we would get some level of improvement (in spinal cord patients) by embracing dendritic growth." The growth is affected by use, meaning the more the neurons are used, the more likely they are to grow, she said.
The study's co-authors -- Nedivi; Peter T. So, an MIT professor of mechanical and biological engineering; Wei-Chung Allen Lee, an MIT brain and cognitive sciences graduate student; and Hayden Huang, a mechanical engineering research affiliate -- used a method called two-photon imaging to track specific neurons over several weeks in the surface layers of the visual cortex in living mice. While many studies have focused on the pyramidal neurons that promote firing, this work looked at all types of neurons, including interneurons, which inhibit the activity of cortical neurons
Source:Massachusetts Institute of Technology