Original news release was issued by Stony Brook University Newsroom.
Memory manipulation is an attractive concept that has only a very short history of successful experiments, but we are certainly making progress in decoding what exactly makes our brains tick. In the most recent news, scientists at Stony Brook University have identified and successfully meddled with the process responsible for determining the strength of a memory. Being able to tune a memory’s strength means being able to suppress it, effectively wiping it from existence.
Brain mechanisms underlying memory are not well understood, but most scientists believe that the region of the brain most involved in emotional memory is the amygdala. Acetylcholine is delivered to the amygdala by cholinergic neurons that reside in the base of the brain. These same neurons appear to be affected early in cognitive decline. Previous research has suggested that cholinergic input to the amygdala appears to strengthen emotional memories.
Memories with strong emotions attached to them are naturally the strongest, both positive and negative. Precisely those who suffer from strong emotional trauma, for example people suffering from post-traumatic stress disorder (PTSD), may benefit from these findings the most.
In the paper, titled “Cholinergic Signaling Controls Conditioned Fear Behaviors and Enhances Plasticity of Cortical-Amygdala Circuits,” Dr. Lorna Role and colleagues used a fear-based memory model in mice to test the underlying mechanism of memory because fear is a strong and emotionally charged experience.
“We essentially created fearless mice by manipulating acetylcholine circuits in the brain,” explained Dr. Role. “The findings provide the basis for research examining novel approaches to reverse post-traumatic stress disorder.”
The team used opto-genetics, a newer research method using light to control cells in living tissue, to stimulate specific populations of cholinergic neurons during the experiments.
Two of the team’s findings stand out. First, when they increased acetylcholine release in the amygdala during the formation of a traumatic memory, it greatly strengthened memory making the memory last more than twice as long as normal. Then, when they decreased acetylcholine signaling in the amygdala during a traumatic experience, one that normally produces a fear response, they could actually wipe out memory.
Because acetylcholine is a natural signaling mechanism and seemingly essential for memory, additional research will center on non-pharmacologic ways to manipulate or fine-tune memory.
“The long-term goal of our research is that we would like to find ways – potentially independent of drug administration – to enhance or diminish the strength of specific memories, the good ones, and diminish the bad ones,” summarized Dr. Role.