Summary: A new study finds that neurons in the prefrontal cortex treat each experience as novel, responding as if every event were unique even when it closely resembles past events. The authors suggest this neural coding may help explain sensations of déjà vu.
Source: Medical University of Vienna
Neuronal activity in the prefrontal cortex encodes each experience as “novel.” Neurons adjust their firing patterns accordingly, even when a new event closely resembles one that occurred before. This key result comes from a study by researchers in the Division of Cognitive Neurobiology at the Medical University of Vienna, recently published in Nature Communications.
“From the brain’s perspective, every experience is unique, no matter how similar it is to something that happened earlier,” explains Hugo Malagon-Vina, a researcher in the Division of Cognitive Neurobiology at MedUni Vienna’s Center for Brain Research and an author of the study. “Neurons in the prefrontal cortex become active each time, as if the experience were entirely new.” Malagon-Vina notes that occasional mismatches in this neuronal activity may underlie the common subjective sensation of déjà vu.
The MedUni Vienna team demonstrated this principle for the first time using an animal model. They recorded and analyzed activity from about 300 individual neurons in regions of the rodent prefrontal cortex, showing how firing patterns shift when animals encounter repeated or similar situations.
Nothing is perceived exactly the same way twice
“Memory clearly exists, but the brain must remain flexible so it can adapt continuously,” says Malagon-Vina. “One way the brain achieves that flexibility is by treating each event as if it were new.” He draws a parallel to the ancient Greek philosopher Heraclitus: “No man ever steps in the same river twice, for it’s not the same river and he’s not the same man.” Heraclitus emphasized that even deliberate actions and similar plans are perceived differently each time; the researchers argue that shifting neuronal activity in the prefrontal cortex offers a biological basis for that observation.
This flexibility in neural coding also supports emotional and cognitive responses that require novelty detection, such as surprise, delight, or the “wow” effect when an experience feels fresh. The study’s findings suggest that the prefrontal cortex represents ongoing behavior and changing strategies rather than fixed rules or static memories. In practical terms, the brain can interpret life-long or recurring experiences as new each time, provided cortical neurons remain healthy and intact.
According to the researchers, these results support the importance of staying mentally active across the lifespan. Neurons in the prefrontal cortex remain capable of adjusting to new information and framing recurring events as distinct experiences — a mechanism that may contribute both to adaptive behavior and to the preserved capacity for curiosity and novelty in healthy aging.
Source: Medical University of Vienna
Publisher: NeuroscienceNews.com (organized summary)
Image source: Image adapted from the Medical University of Vienna news release
Original research: Open access research article in Nature Communications (DOI: 10.1038/s41467-017-02764-x).
MLA: Medical University of Vienna. “Every Experience the Brain Perceives is Unique.” NeuroscienceNews, 20 February 2018.
APA: Medical University of Vienna (2018, February 20). Every Experience the Brain Perceives Is Unique. NeuroscienceNews.
Chicago: Medical University of Vienna. “Every Experience the Brain Perceives Is Unique.” NeuroscienceNews. (accessed February 20, 2018).
Abstract
Fluid network dynamics in the prefrontal cortex during multiple strategy switching
Coordinated shifts in neuronal activity within the prefrontal cortex are linked to adaptations in behavioral strategies when animals switch from one rule to another. Network dynamics associated with repeated rule changes are, however, not well understood. The study shows how firing rates of individual neurons in the prelimbic and cingulate regions correlate with rats’ performance when they repeatedly change navigation strategies between allocentric and egocentric rules. The population activity remains stable while one rule is applied, but shifts into a different firing state when a new rule is learned. Notably, if the same rule is presented again within the same session, neuronal firing does not revert to the prior state; instead, a distinct activity state forms. These data suggest that prefrontal neuronal firing primarily represents changes in strategy and task performance rather than encoding fixed, specific rules.