Researchers were able to delete one of two memories stored in the neuron of a marine snail without harming the other. Photo by Schacher Lab/Columbia University Medical Center
June 22 (UPI) -- In a series of experiments, neuroscientists were able to selectively delete different types of memories stored a single neuron belonging to a marine snail.
The feat, detailed in the journal Current Biology, suggests problematic memories -- like those responsible for PSTD and anxiety -- in the human brain could be excised without harming other memories.
When the brain stores a traumatic experience in its memory bank, the memory is actually stored in multiple forms. Each memory can include bits of incidental information from the experience. Years later, these incidental, or neutral, memories can trigger panic attacks and severe anxiety.
"The example I like to give is, if you are walking in a high-crime area and you take a shortcut through a dark alley and get mugged, and then you happen to see a mailbox nearby, you might get really nervous when you want to mail something later on," Samuel Schacher, a professor of neuroscience at Columbia University Medical Center, said in a news release.
Schacher and his colleagues are searching for ways to get rid of symptom-causing non-associative memories without harming longterm associative memories, which can help people make good decisions.
Researchers assumed the brain forms all longterm memories -- whether non-associative or associative -- in the same way, by increasing and maintaining strength of synaptic connections. But the latest study suggests non-associative and associative memories are stored and maintained in different ways.
In a series of tests, scientists manipulated two sensory neurons connected to a single motor neuron in a marine snail model. The stimulation of one sensor neuron induced the formation of an associative memory and stimulation of the other induced a non-associative memory.
The experiments showed two different protein were used to increase the synaptic strength during each memory's formation. By blocking one specific protein molecule, researchers were able to delete one memory without harming the other.
Researchers say additional studies of the behavior Protein Kinase M molecules is needed to determine which drugs might work to delete non-associative memories in the human brain.
"Memory erasure has the potential to alleviate PTSD and anxiety disorders by removing the non-associative memory that causes the maladaptive physiological response," said Jiangyuan Hu, a research scientist in psychiatry at CUMC. "By isolating the exact molecules that maintain non-associative memory, we may be able to develop drugs that can treat anxiety without affecting the patient's normal memory of past events."