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A study found that memory is controlled by the dopamine circuit

Detection of the “transitory forgetting” mechanism; It stops the thought without canceling the long-term memories

JUPITER, Florida – In a historical neurobiology study, scientists from Scripps Research discovered a memory portal system that uses the neurotransmitter dopamine to direct forgetting, a temporary loss of memory that automatically returns.

The study adds a new pin to the evolving map for scientists of how learning, memory and active forgetting work, says professor of neuroscience Scripps Research Ron Davis.

“This is the first time that a transient memory lapse mechanism has been discovered,” says Davis. “There is every reason to believe, due to conservation biology, that a similar mechanism exists in humans as well.”

The study, “The Dopamine-Based Mechanism for Transient Forgetting,” was published Wednesday in the journal nature.

Everyone has experienced fleeting forgetfulness. A name that sits on the tip of our tongue, but only pops up after the meeting. We enter a room and forget the reason for our entry – until we leave. Certainly annoying. But is it a mental disorder, or is absence a feature of a normal brain? Has the elusive memory been erased and somehow restored, or just hidden for some time? How exactly transient forgetting works is not yet known.

To get an answer, Davis’ team has worked on the common fruit fly, a model that neurobiologists have preferred for decades due to its relatively simple brain structure, ease of study, and translatability into more complex animals.

The team underwent a series of exercises, teaching them to link the smell to an unpleasant foot shock. Then they monitored many interfering stimuli, such as blue light or puffs of air, which distracted the flies, so they temporarily forgot the negative association of the scent. Interestingly, the stronger stimulus resulted in longer periods of forgetfulness.

Additional biochemical studies revealed a single pair of dopamine-releasing neurons in flies, called PPL1-α2α’2, which directed transient forgetfulness. Dopamine sent from other neurons did not have the same effect. Neurons activate dopamine receptors called DAMB on axons extending from the nerve cells in the memory processing center in the brain of Drosophila, which is called the mushroom body.

Davis says that activating the transient forgetfulness circuit did not erase the flies’ long-term memory retrieval, suggesting that transient forgetting does not affect the effects of permanent and consolidated memory or engrams obtained over time.

Interestingly, they found that the flies’ memory performance recovered after the fleeting forgotten period ended, says the paper’s first author, John Martin Sabandal, a graduate student at Scripps Research, who worked with team scientist Jacob Berry, Ph.D., in the team’s lab at Planet. Jupiter, Florida.

“Can we do better if some memories are suppressed on others – can we learn or adapt to situations better? Nobody knows. This is the kind of questions that will be explored in the future,” says Sabandal. “We found, temporarily, that There is a potential memory reserve that cannot be expressed at a particular moment. ”

The mechanisms behind long-term memory acquisition have been carefully studied and standardized over the past 40 years, Davis says, but forgetting has been overlooked until recently. It proves to be an amazing field. In 2012, Davis’ group found a mechanism to direct permanent forgetfulness, and found it to be an ongoing and active process, and it seemed essential for normal brain function.

“You can imagine that we have thousands of memories that happen every day in our life, and the brain does not have the ability to remember or encode all of those memories. So there is a need to erase those memories that are unrelated to our existence and our daily life,” Davis says.

Taken together, it’s increasingly clear that much of what we think of as amnesia is not the result of a break in bonds or age-related deterioration, but an important feature, and one essential to survival, Davis says. He adds that more work awaits us.

“We now know that there is a specific receptor in the memory center that receives the forgetting signal in transit from dopamine. But we don’t yet know what is happening downstream. What does this receptor do for neuronal physiology that temporarily impedes memory retrieval? This is the next major goal, to understand How this block in recall occurs through dopamine receptor activation, “Davis says. “We are just beginning to understand how the brain causes transitory forgetfulness.”

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https: //www.Scripps.Edo /News & Events /Press room /2021 /20210120-davis-transient-forgetful-nature.programming language

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