Not that small snails and neurons have all that much going on in the memory department, mind you. But that was the point, the researchers said. The study's goal was to isolate a protein kinase and process that snails and mammals share (which the researchers suspected played a key role in memory retention) and to test the effect of inhibiting that activity in an animal with a very simple neurological system.

When researchers prodded the snails' abdomens, the snails responded with a reflexive contraction. But normally, that contraction lasted only a few seconds. After "training" the snails with electric shocks associated with the prodding, however, the contractions lasted up to 50 seconds. A week later, prodding the snails still resulted in contractions lasting 30 seconds or longer, indicating to researchers that the snails "remembered" the electric shocks, and that the memory had been encoded into "long-term" memory in their systems.

If the researchers inhibited the activity of a specific protein kinase called PKM, however, the snails then responded to being prodded with only the standard two- or three-second contraction. Their memory of the electric shock training was effectively erased.

Clearly, there's a big gap between inhibiting long-term memory in the synapse between two neurons in a simple marine snail and inhibiting long-term memories in the highly complex structure of a human mind. Even if the PKM protein kinase were to prove pivotal in humans as well, and could be reliably inhibited, researchers would still have to figure out how to locate and target specific memories in the brain. Otherwise, all of a person's memories could be erased—not just the traumatic ones.

Nevertheless, the experiment is something of a breakthrough and could be the first step in developing therapies to "damp down" or erase traumatic memories in people suffering from debilitating cases of post-traumatic stress disorder (PTSD). Given that the U.S. Army suicide rate has reached a 27-year high, and that nearly 20 percent of returning veterans from Iraq and Afghanistan test positive for PTSD (the Department of Veterans Affairs reported last year that over 170,000 returning veterans had been diagnosed with PTSD), the idea of being able to wipe out the traumatic memories causing all that pain is appealing.

Indeed, few adults reach the age of 40 or 50 without accumulating some memories that still make the heart ache in the middle of the night, even if the remembered event happened a very long time ago. But if we had the ability to erase those painful or traumatic memories, would we really want to do that?

Part of my hesitancy stems from the seeming inevitability of the Law of Unintended Consequences. As hard as professionals might try to anticipate any collateral effects of erasing a traumatic memory, odds are good that there'd be some new and unexpected problems created by the technique. But I also wonder if it's really possible to eliminate significant memories, even ones that are traumatic, and erase only the pain and damage—and not also an important piece of who that person is or has become.