New study of snail neurons suggests memories that trigger anxiety, PTSD could be ‘erased’ without affecting normal memory of past events
Different types of memories stored in the same neuron of the marine snail Aplysia can be selectively erased, according to a new study by researchers at Columbia University Medical Center (CUMC) and McGill University and published today in Current Biology.
The findings suggest that it may be possible to develop drugs to delete memories that trigger anxiety and post-traumatic stress disorder (PTSD) without affecting other important memories of past events.
During emotional or traumatic events, multiple memories can become encoded, including memories of any incidental information that is present when the event occurs. In the case of a traumatic experience, the incidental, or neutral, information can trigger anxiety attacks long after the event has occurred, say the researchers.
“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,” says Samuel Schacher, PhD, a professor of neuroscience in the Department of Psychiatry at CUMC and co-author of the paper. In the example, fear of dark alleys is an associative memory that provides important information—e.g., fear of dark alleys—based on a previous experience. Fear of mailboxes, however, is an incidental, non-associative memory that is not directly related to the traumatic event.
“One focus of our current research is to develop strategies to eliminate problematic non-associative memories that may become stamped on the brain during a traumatic experience without harming associative memories, which can help people make informed decisions in the future—like not taking shortcuts through dark alleys in high-crime areas,” Dr. Schacher adds.
Brains create long-term memories, in part, by increasing the strength of connections between neurons and maintaining those connections over time. Previous research suggested that increases in synaptic strength in creating associative and non-associative memories share common properties. This suggests that selectively eliminating non-associative synaptic memories would be impossible, because for any one neuron, a single mechanism would be responsible for maintaining all forms of synaptic memories.
The new study tested that hypothesis by stimulating two sensory neurons connected to a single motor neuron of the marine snail Aplysia; one sensory neuron was stimulated to induce an associative memory and the other to induce a non-associative memory.
By measuring the strength of each connection, the researchers found that the increase in the strength of each connection produced by the different stimuli was maintained by a different form of a Protein Kinase M (PKM) molecule (PKM Apl III for associative synaptic memory and PKM Apl I for non-associative). They found that each memory could be erased – without affecting the other — by blocking one of the PKM molecules.
In addition, they found that specific synaptic memories may also be erased by blocking the function of distinct variants of other molecules that either help produce PKMs or protect them from breaking down.
The researchers say that their results could be useful in understanding human memory because vertebrates have similar versions of the Aplysia PKM proteins that participate in the formation of long-term memories. In addition, the PKM-protecting protein KIBRA is expressed in humans, and mutations of this gene produce intellectual disability.
“Memory erasure has the potential to alleviate PTSD and anxiety disorders by removing the non-associative memory that causes the maladaptive physiological response,” says Jiangyuan Hu, PhD, an associate research scientist in the Department of Psychiatry at CUMC and co-author of the paper. “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.”
“Our study is a ‘proof of principle’ that presents an opportunity for developing strategies and perhaps therapies to address anxiety,” said Dr. Schacher. “For example, because memories are still likely to change immediately after recollection, a therapist may help to ‘rewrite’ a non-associative memory by administering a drug that inhibits the maintenance of non-associative memory.”
Future studies in preclinical models are needed to better understand how PKMs are produced and localized at the synapse before researchers can determine which drugs may weaken non-associative memories.
The Latest on: Erasing memories
Martha Hart Issues Statement After Bret Hart Claimed She 'Erased' Owen Hart's Memory
on July 20, 2018 at 9:50 am
Martha Hart, PhD, released the following statement today in response to published comments attributed to the former WWE wrestler, Bret Hart: The suggestion by Bret Hart that I am "erasing" the memory ... […]
Erasing the memory of T cells could reverse vitiligo symptoms
on July 18, 2018 at 11:16 am
Researchers have found that targeting the activity of a class of T cells restores pigmentation of the skin in a mouse model of vitiligo. Their discovery could lay the foundation for new vitiligo thera... […]
Daley Blind's Manchester United exit erases almost all memories of Van Gaal
on July 18, 2018 at 4:15 am
Jose Mourinho's methodical and ruthless quest to erase Louis Van Gaal from the collective Old Trafford memory took another step forward yesterday as the club announced Daley Blind had returned to Ajax ... […]
Fair memories spun in summer sun
on July 18, 2018 at 2:26 am
Lavarnway recalled his own childhood memories at the fair ... They can draw on the blackboard. We can always erase it.&rdquo […]
Fitri wants to erase memories of 2014 Asian Games
on July 15, 2018 at 11:30 am
In Incheon, Malaysia failed to win a medal by finishing fourth behind India, Pakistan and South Korea. The Indonesia edition is crucial as the gold medallists will qualify for the 2020 Tokyo Olympic G... […]
Owen Hart’s Widow BLASTS Bret Hart for Claiming She’s Erasing Memory of Her Husband
on July 12, 2018 at 11:08 am
Bret Hart recently stated Owen Hart‘s widow is doing more to erase his memory than honor it, and now she’s speaking out to put him on blast for the “disrespectful and cruel comments.” “The suggestion ... […]
Martha Hart Responds To Bret Hart's Comments About Erasing Owen's Memory
on July 12, 2018 at 9:44 am
Bret Hart recently made comments to CBS In This Corner podcast regarding his late-brother Owen Hart's wife Martha Hart. Since Owen's tragic death in 1999, Martha won an out of court settlement and has ... […]
Samuel Umtiti keen to banish memory of Euro 2016 by lifting the World Cup
on July 10, 2018 at 3:30 pm
Match-winner Samuel Umtiti is targeting World Cup glory as he attempts to erase the memory of his Euro 2016 heartache. The Barcelona defender headed France to a 1-0 semi-final victory over Belgium in ... […]
Physics Is Erasing Your Memory
on July 10, 2018 at 11:58 am
You might store your most precious memories in diary passages or in photos backed up on a hard drive. But thanks to physics, no memory can last forever—not in a diary, not in a hard drive, not even in ... […]
UT neuroscientist working on method to remove fear memories and help PTSD patients
on July 9, 2018 at 1:28 pm
Right now, the science is being tested in mice, training them to establish fear memories, by way of electric shock, and then erasing those memories through carbon dioxide, which makes the memory unsta... […]
via Google News and Bing News