Bangalore (ISJ) ? A study by Indian scientists revealed, even a single instance of severe stress can lead to delayed and long-term psychological trauma.
The study by a team of scientists at the National Centre for Biological Sciences (NCBS) and the Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore unravelled the key molecular and physiological processes that could be driving changes in brain architecture.
The team, led by Dr. Sumantra Chattarji has shown a single stressful incident can lead to increased electrical activity in a brain region known as the amygdala. This activity is delayed, occurring ten days after a single stressful episode, and is dependent on a molecule known as the N-Methyl-D-Aspartate Receptor (NMDA-R), a protein on nerve cells known to be crucial for memory functions.
The amygdala is small, almond-shaped groups of nerve cells located deep within the temporal lobe of the brain. This region of the brain is responsible for emotional reactions, memory and making decisions. Changes in the amygdala are linked to the development of Post-Traumatic Stress Disorder (PTSD), a mental condition that develops in a delayed fashion after a harrowing experience.
?We showed that our study system is applicable to PTSD. This delayed effect after a single episode of stress was reminiscent of what happens in PTSD patients,? said Chattarji, who heads the Centre for Brain Development and Repair at inStem. ?We know that the amygdala is hyperactive in PTSD patients. But no one knows as of now, what is going on in there.?
Tests on rats have shown a single instance of acute stress had no immediate effect on its amygdala. But ten days later, these animals began to show increased anxiety, and delayed changes in the architecture of their brains, especially the amygdala. Stress seems to have caused the formation of new nerve connections called synapses in this region of the brain. However, until now, the physiological effects of these new connections were unknown.
?So we have established for the first time, a molecular mechanism that shows what is required for the culmination of events ten days after a single stress,? Chattarji explained. ?In this study, we have blocked the NMDA Receptor during stress. But we would like to know if blocking the molecule after stress can also block the delayed effects of the stress. And if so, how long after the stress can we block the receptor to define a window for therapy,? he added.
