How Your Brain Hides Painful Memories

Suppressed memories, locked away somewhere in our brain’s attic. It’s hard to believe but the brain does have an amazing capacity to hide certain memories from us. It’s a way of protecting us from something profoundly disturbing, such as being abused as a child, or witnessing the horrors of war. But these buried, unconscious memories can later trigger devastating problems like depression, PTSD and anxiety. It’s difficult for therapists to treat these psychological symptoms without being able to address the root cause of someone’s trauma.

New research from Northwestern University has shed light on exactly how the brain hides memories, which may help therapists assist patients in the future. Researchers gave mice a drug that stimulates extra-synaptic GABA receptors in their brains. (Extra-synaptic GABA receptors alter the brain’s state, making us feel alert or sedated; sleepy or awake.) Next, the mice were placed in a box and given a brief, mild electric zap. When they were returned to the same box the next day, they didn’t seem alarmed and moved about freely. But, when the mice were given the same drug to tweak their extra-synaptic GABA receptors, and put back in the box, they froze in fear. In other words, they were able to easily access the memory of being shocked when they were in the same mental state they had been in when they were initially shocked.

“The brain functions in different states, much like a radio operates at AM and FM frequency bands,” wrote principal investigator Dr. Jelena Radulovic, a professor at the Northwestern University Feinberg School of Medicine. “It’s as if the brain is normally tuned to FM stations to access memories, but needs to be tuned to AM stations to access subconscious memories.”

The findings imply, the researchers say, that in response to traumatic stress, some people’s brains don’t go the usual route of making memories, but instead switch on the extra-synaptic GABA system to form inaccessible memories.

According to Radulovic, the research “could eventually lead to new treatments for patients with psychiatric disorders for whom conscious access to their traumatic memories is needed if they are to recover."