To: From: Sent: t i t...11111IM Subject: (no subject) TRANSPLANTED STEM CELLS FORM PROPER BRAIN CONNECTIONS In new animal study, neurons developed from stem cells successfully wired with other brain regions Washington, DC — Transplanted neurons grown from embryonic stem cells can fully integrate into the brains of young animals, according to new research in the Jan. 20 issue of The Journal of Neuroscience. Healthy brains have stable and precise connections between cells that are necessary for normal behavior. This new finding is the first to show that stem cells can be directed not only to become specific brain cells, but to link correctly. In this study, a team of neuroscientists led by James Weimann, PhD, of Stanford Medical School focused on cells that transmit information from the brain's cortex, some of which are responsible for muscle control. It is these neurons that are lost or damaged in spinal cord injuries and amyotrophic lateral sclerosis (ALS). "These stem cell-derived neurons can grow nerve fibers between the brain's cerebral cortex and the spinal cord, so this study confirms the use of stem cells for therapeutic goals," Weimann said. To integrate new cells into a brain successfully, the researchers first had to condition unspecialized cells to become specific cells in the brain's cortex. Cells that were precursors to cortical neurons were grown in a Petri dish until they displayed many of the same characteristics as mature neurons. The young neurons were then transplanted into the brains of newborn mice — specifically, into regions of the cortex responsible for vision, touch, and movement. Until now, making these proper cellular connections has been a fundamental problem in nervous system transplant therapy. In this case, the maturing neurons extended to the appropriate brain structures, and, just as importantly, avoided inappropriate areas. For example, cells transplanted into the visual cortex reached two deep brain st