Of Mice and "Extreme" Men

When Seattlest was a wee one of about 5 years, our house was tucked up in the eastern foothills of Salt Lake City, and there wasn't a flat street to be found nearby. One morning when two much older boys went flying down the hill by our house at full tilt on skateboards, we turned to mom and pined for one of our own. Our young body rushed with endorphins merely at the sight of watching them go by; we felt no fear, only exhiliration. Sadly, there was no skateboard under the Xmas tree for us that year. Mom was having none of that.

The crux of our story is: genetically speaking we can't explain our need for speed. Neither parent comes close to our adrenaline addiction, though Dad gets credit for getting us started downhill skiing only a few years after Santa passed on gifting us a skateboard. Nonetheless, local scientists at the Hutch claim to have made a step in the direction of understanding a genetic link to risk-taking behavior, or at least to how emotion and memory play together to influence behavior.

The short version of the research findings is that mice deficient in a particular gene (neuroD2) have impaired development of the amygdala, an area of the brain known to be involved in emotion and in the relationship between emotion and memory. These neuroD2-lacking mice have less fearful responses to fear-inducing situations than normal mice. Also, even when not in stressful situations, they appear to choose more "risky" behavior compared to mice with normal levels of neuroD2.

What does this mean for us humans? This type of research can't lend any solid conclusions along those lines quite yet. It is also plagued by a particularly pesky problem:

Long-term behavioral studies of mice with no neuroD2 genes were not possible because these mice die within a few weeks of birth.