Is the memory gone or hidden? New research decodes the brain's forgetting mechanisms

But with the neuroscience community's research on the mechanism of forgetting in recent years, a complex picture has emerged: forgetting is not simply "elimination of memory".
example of the phenomenon of "words in the mouth": names, birthdays, cell phone numbers that are suddenly forgotten suddenly appear in our minds after a while.
neuroscientist at the Scripps Institution in Florida, USA, unveiled this unique mechanism in a study published January 21 in Nature.
-driven forgotten "happiness molecule" dopamine is thought to be the brain's release of "fast-splitting fun", a common neurotonic condition that transmits complex and diverse global messages to different regions of the brain.
recent years, dopamine's role in oblivion has emerged.
in a series of experiments, the researchers not only confirmed the importance of dopamine for endogenetic forgetting, but also found dopamine neurons responsible for promoting forgetting, and even dopamine subjects responsible for performing forgetting functions.
all this, thanks to the black belly fruit fly.
's brain has about 100,000 neurons -- far less than the 86 billion neurons in the human brain -- but the fruit fly's brain is complex enough for us to use it to explore biological memory and forgetting.
in the brain of 100,000 neurons, there is an area called the "back and outer frontal brain region 1" (PPL1), which contains 12 dopamine neurons.
Of these 12 dopamine neurons, many send information to the mushroom body (the sensory information processing center of the fruit fly) and release dopamine on the adynorta of the various neurons in the mushroom body (the primary location where the neurons receive information), thus regulating signal integration of the mushroom body neurons.
neuroscientist has long divided the mushroom body into many regions based on the gene expression and anatomical location of various neurons in the mushroom body.
, the mushroom body neurons received information from PPL1 dopamine neurons and mediated endogenous (long-term) oblivion.
past studies support the role of dopamine-mediated forgetting, which provides a valuable cornerstone for this study.
Blocking extraction but not destroying the memory itself In this study, Ronald Davis of the Scripps Institute, along with doctoral student John Sarbandal and postdoctoral researcher Jacob Berry, followed PPL1 to the mushroom body in an attempt to uncover the mysterious mechanisms of instant forgetting.
and others trained fruit flies in aversion to olfactory condition reflexes.
Put the trained fruit flies in a T-word maze and place "bad smells" (representing the smell of electric shocks) and "neutral smells" (smells not connected to electric shocks) on both sides of the intersection to see which way they go.
results were the same as expected: trained fruit flies were more likely to avoid "bad smells" and move in the direction of "neutral smells".
then, to study instant forgetting, Davis and others briefly jetted, electrocuted, or blue-lighted fruit flies before choosing "left or right."
the results were not surprising: fruit flies were dizzy under the influence of disturbing stimuli and stopped avoiding "bad smells" at all.
interestingly, if fruit flies were tested again an hour after the disturbance, they could recall which one was "bad smell" and actively avoid choosing another path.
researchers succeeded in suppressing the memory of fruit flies by directly stimulating dopamine neurons in PPL1, and if they inhibited the output of these dopamine neurons, fruit flies did not produce instantaneous forgetting under interference.
, dopamine neurons from PPL1 to the mushroom body alpha2'2 are the most important.
suggests that there is a "memory memory" in the mushroom body alpha 2 alpha'2 neurons, while dopamine acts as a "gate control".
, however, one thing is important in instant forgetting: it is short-lived, and after minutes to hours, the ability to recall is restored.
suggests that instant forgetting (the activity of PPL1-alpha2 alpha'2 dopamine neurons) does not destroy memory storage, but simply disconnects the "circuit" of memory.
this can also be proved by experiments: in fruit flies where dopamine neurons are active, the "memory neurons" in the mushroom body are actually as active as when the dopamine neurons are inactive.
, dopamine neurons block memory extraction, but do not destroy the memory itself.