The Mechanics of Trauma

Could these drugs work later, with distant trauma?
It's possible. We also know that each PTSD reaction is a recall of the painful memory. Drugs could be taken after a retriggering of the PTSD, when the memory is moving from short-term to long-term again. Some of the current medications for PTSD are antidepressants, which just remove anxiety secondary to the trigger of PTSD.

Why don't we don't have flashbacks to positive memories like our first kiss when we're hyped up?
The release in noradrenaline affects the amygdala, which is mostly activated by bad memories. Positive memories are distributed within different brain regions.

You did your research looking at slices of a rat's brain under a microscope. Wouldn't a human brain be very different?
The neural mechanisms are extremely similar, and you could see the same brain structure. You could locate the amygdala, the part of the brain associated with negative emotions. In our earlier study we showed that fear conditioning led rats to have more electrical currents coming to the amygdala. Looking at slices of the brain, we recorded the tiny electrical currents flowing between the neurons. This time, we injected the slices of brain with noradrenaline and measured the changes in the electrical currents. We found that by adding the noradrenaline, it takes less stimulus to create "LTP" or long term potentiation, when the increase in currents [in the amygdala] becomes long-term [which is associated with PTSD].

What's the next step?
We want to inject the animals with blockers for noradrenalin receptors before fear-conditioning to see if that would suppress the creation of long-term memories. This would help us see whether drugs that block noradrenalin receptors in the amygdala could be helpful.

© 2007