A car that looks like your ex, barks like your dead pet, smells like hospital food: There’s no shortage of stimuli that can be unpleasant. Fortunately, our brains are trained to block intrusive thoughts by acting directly on the memory area. According to work published in, this blockage can happen so fast that we will not even know about it Journal of Neurosciences,
an area of the brain that is able to block a thought or memory
Deciding not to think about something is a command that seems difficult to follow. And yet, there is a mechanism dedicated to this blockage in our brain, whose conduction is in a small region located in the heart of our brain: the dorsal anterior cingulate cortex (ADCC). This is the brain region that the researchers activated in 24 of the study subjects. were trained to remember pairs of words related to each other (for example train – dor or africa – beech), then they were asked to think of only one word, referred to as “recall” , and no other. “Then there is a conflict between the goal of not thinking about the memory associated with a recall and the inevitable tendency of that recall to automatically lead to the retrieval of the unwanted memory.”, explains Michael Anderson, a cognitive expert at the University of Cambridge (United Kingdom) and co-author of the study. It is this conflict that activates the CCAD, an area of the brain known for its cognitive control functions. To prevent memory from invading consciousness, CCAD must act quickly!
a blockage is sometimes so severe that it can cause fainting
And indeed, its speed of action is astonishing. Because if CCAD manages to suppress memory after it emerges, researchers find that it can inhibit this mechanism even before the memory is ejected! Scientists speak of proactive (early) and reactive (later) control. Seeing the difference between the two responses, which play out within a few hundred milliseconds, was no small feat.
A car that looks like your ex, barks like your dead pet, smells like hospital food: There’s no shortage of stimuli that can be unpleasant. Fortunately, our brains are trained to block intrusive thoughts by acting directly on the memory area. According to the work published in, this blockage can happen so fast that we will not even know about it Journal of Neurosciences,
an area of the brain that is able to block a thought or memory
Deciding not to think about something is a command that seems difficult to follow. And yet, there is a mechanism dedicated to this blockage in our brain, whose conduction is in a small region located in the heart of our brain: the dorsal anterior cingulate cortex (ADCC). This is the brain region that the researchers activated in 24 of the study subjects. were trained to remember pairs of words related to each other (for example train – dor or africa – beech), then they were asked to think of only one word, referred to as “recall” , and no other. “Then there is a conflict between the goal of not thinking about the memory associated with a recall and the inevitable tendency of that recall to automatically lead to the retrieval of the unwanted memory.”, explains Michael Anderson, a cognitive expert at the University of Cambridge (United Kingdom) and co-author of the study. It is this conflict that activates the CCAD, an area of the brain known for its cognitive control functions. To prevent memory from invading consciousness, CCAD must act quickly!
a blockage is sometimes so severe that it can cause fainting
And indeed, its speed of action is astonishing. Because if CCAD manages to suppress memory after it emerges, researchers find that it can inhibit this mechanism even before the memory is ejected! Scientists speak of proactive (early) and reactive (later) control. Seeing the difference between the two responses, which play out within a few hundred milliseconds, was no small feat. To achieve this, the researchers used a combination of two methods: functional MRI, an imaging technique to see which areas of the brain are active, and electroencephalogram (EEG), which detects signals of brain activity. . Very fine with time. ,fMRI has excellent spatial resolution, but it has poor temporal resolution, activation cannot be determined for up to a second during the fMRI task. On the other hand, EEG can differentiate activity down to milliseconds, but the spatial localization is worse.”, explains Michael Anderson. Thus fMRI made it possible to determine the implication of CCAD in the suppression of memory retrieval, but not the timing of its action.
The toggle runs 500 milliseconds after the subject of the experiment is shown the word reminder. Why this specific delay? Quite simply because it corresponds to the time required for a visual stimulus (the written word) to activate the hippocampus, a memory area, and trigger the conscious recovery of the unwanted memory (the second word) there. ,In other words, anything that happens before 500 milliseconds most likely happens when the associated memory enters consciousness.“Specifies Michael Anderson. The team then looked at two types of activation of CCAD, early (350–400 ms) and late (500–700 ms). These observations suggestBoth proactive control before recall and reactive control in response to intrusion“, they conclude in their study.
Early control of intrusive memory is more effective
The surprises don’t end there, as researchers have found early control after reducing brain activity triggered by CCAD. In contrast, late controls resulted in increased CCAD activity. ,Active control mechanisms allow more successful forgetting than reactive control mechanisms”, explains Michael Anderson. ,I assumed the opposite would happen, i.e. forgetting would be more effective if people actively removed something from their awareness.In fact, during active surveillance the memory faded so quickly that no further brain activity was needed. Instead of turning off the taps in the homes, the water supply was cut off.
But the system isn’t perfect, as this active mechanism is probably only used when we can anticipate that an unwanted memory will be sought, explain the researchers. In real life, the stimuli we encounter often lead to these thoughts by surprise. The reactive mechanism, the latter, therefore allows “To eliminate the things that ‘pass’ and come to mind anyway”, explains Michael Anderson.
treat post traumatic stress disorder
This finding proves that the human brain can filter out intrusive thoughts even before they are fully conscious, summarizes Michael Anderson. it remains to be clarified “Identity System”“CCAD that allows it”Identify emerging material that could be hazardous,
If this function is necessary, it is because it has therapeutic effects. ,The more detailed our understanding of how we handle unwanted thoughts, the more able we will be to apply this knowledge to disorders such as post-traumatic stress disorder.“Or PTSD, Michael Anderson estimates. Affecting 6 to 9% of the population, PTSD is characterized by the untimely intrusion of vivid memories and sensations, especially those related to the traumatic event at the origin of the disorder. Previous Inserm work published Science In 2020 and so on, this new study also revealed that PTSD was associated with dysfunction of memory control mechanisms. When faced with a task similar to the subjects in the current study, those with PTSD were unable to block the intrusive memory of a word they should not have thought about.
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