Source: University of Texas Southwestern Medical Center
Date: March 30, 2011
Summary:
DALLAS –– Researchers from UT Southwestern Medical Center have described for the first time how the brain’s memory center repairs itself following severe trauma – a process that may explain why it is harder to bounce back after multiple head injuries.
The study, published in The Journal of Neuroscience, reports significant learning and memory problems in mice who were unable to create new nerve cells in the brain’s memory area, the hippocampus, following brain trauma.
The scientists developed unique transgenic mice that were unable to create hippocampal neurons when exposed to a usually harmless chemical called ganciclovir soon after brain injury. Four groups of these transgenic mice received either sham surgery or a controlled cortical injury (CCI) to mimic the diffuse damage of a moderate to severe head injury, and two of the groups were exposed to ganciclovir, Dr. Kernie said.
After a month – the time earlier experiments indicated it takes for neural stem cells to mature and integrate as neurons into the hippocampus – the researchers gave the mice a learning task called the Morris water maze in which the mice had to find a white platform hidden in a white pool of water. On the first day of learning the task, there were no group-noteworthy differences in swim speed, indicating no motor impairment in the test mice. During the next 10 days, however, the test group spent more time swimming along the edges of the tank, and they traveled longer distances to reach the platform.
