Mortified Mouse
Scientists at Emory University, extending the work of others scientists who have identified the amygdala (an almond-shaped brain region) as key to our fear response, have shown that the prelimbic cortex plays a role, too.
Kerry Ressler, MD, PhD, and his team found that without a critical growth factor in the prelimbic cortex mice become less prone to remember a previously frightening experience. This finding could benefit the diagnosis and treatment for anxiety disorders such as post-traumatic stress disorder and phobias.
BDNF (brain-derived neurotrophic factor) has been called Miracle-Gro for brain cells. The protein protects cells from stress and stimulates them to forge new connections. Previous studies had shown that blocking BDNF’s action in the amygdala made it more difficult for fear memories to take hold.
“The prelimbic cortex is part of the medial prefrontal cortex, which appears to be important for emotional regulation in rodents as well as humans,” Ressler says. “Evidence is building that these regions may be dysregulated or even over-active in fear and anxiety disorders in humans.”
“This work is important for extending our understanding of how BDNF is important for neuronal plasticity, learning and memory,” Ressler says. “Together with our previous work, these data suggest that preventing neural plasticity in very precise, but critical brain regions, can have vastly different effects on emotional memory.
“It is becoming increasingly clear that these prefrontal cortex regions are functionally associated with regions of the brain known for a long time to be involved in emotion, such as the amygdala and hippocampus,” he adds. “Understanding the molecular and cellular mechanisms of these connections in rodent models will provide scientists a better understanding of how these similar areas are functioning in humans.”