Suspect list shortens for maternal aggression's bra...( Scientists studying the origins of a...)

Scientists studying the origins of aggression have highlighted areas in the brains of mouse mothers that may generate fierce attacks on males who pose a potential threat to their pups.

The findings will be presented by Johns Hopkins University postdoctoral researcher Stephen Gammie at this week's annual meeting of the Society for Neuroscience in New Orleans. Gammie says the results are an important step towards pinning down the origins of this type of aggressive behavior in the mouse brain, an accomplishment that could help scientists better probe aggression's origins in humans.

To prevent strange male mice from harming their offspring, female mice with pups normally attack any such mouse who comes into their area. A few mouse moms, however, fail to show this response. Gammie divided mice into groups based on this distinction, compared the two groups for presence of compounds related to brain activity, and was able to identify four brain areas that were active in the aggressive moms but not in the non-aggressives.

Given the mouse brain's small size, cutting down the list of suspects for production of aggression might seem an unlikely or unimportant step. But even the humble mouse brain has sufficient structural and biochemical complexity to resist giving up its secrets easily, Gammie says.

"By taking advantage of natural variation in aggression, our study decreased the odds of confusing aggression control mechanisms with other areas of the brain activated when a strange male mouse approaches," says Gammie. "For example, areas of the brain that are involved in seeing and smelling the males become active in both groups of mouse moms. Areas that become active only in the aggressive moms have a good chance of being linked to production of the primary difference in behavior, the aggression."

Gammie's postdoctoral mentor, Hopkins psychology and neuroscience professor Randy Nelson, was one of a g
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Contact: Michael Purdy
mcp@jhu.edu
410-516-7160
Johns Hopkins University
7-Nov-2000