Many neuroscientists believe the loss of the brain region known as the amygdala would result in the brain's inability to form new memories with emotional content. New UCLA research indicates this is not so and suggests that when one brain region is damaged, other regions can compensate.
The research appears this week in the early online edition of the journal Proceedings of the National Academy of Sciences (PNAS).
"Our findings show that when the amygdala is not available, another brain region called the bed nuclei can compensate for the loss of the amygdala," said the study's senior author, Michael Fanselow, a UCLA professor of psychology and a member of the UCLA Brain Research Institute.
"The bed nuclei are much slower at learning, and form memories only when the amygdala is not learning," he said. "However, when you do not have an amygdala, if you have an emotional experience, it is like neural plasticity (the memory-forming ability of brain cells) and the bed nuclei spring into action.
Normally, it is as if the amygdala says, 'I'm doing my job, so you shouldn't learn.' With the amygdala gone, the bed nuclei do not receive that signal and are freed to learn."
The amygdala is believed to be critical for learning about and storing the emotional aspects of experience, Fanselow said, and it also serves as an alarm to activate a cascade of biological systems to protect the body in times of danger.