HMN 2025: How A sign that by no means repeats—how the mind creates bookmarks to map time

The mind does not merely register time—it buildings it, in keeping with new research from the Kavli Institute for Systems Neuroscience revealed in Science.

The analysis workforce led by NTNU’s Nobel Laureates May-Britt and Edvard Moser, from the Kavli Institute for Systems Neuroscience, is already recognized for his or her discovery of the mind’s sense of place.

Now they’ve proven that the mind additionally weaves a tapestry of time: The mind segments and organizes occasions into experiences, inserting distinctive bookmarks on them in order that our lives do not turn out to be a blurry stream, however relatively a sequence of significant moments and recollections we will revisit and be taught from.

We reside in a steady stream of fleeting sensory data. How will we handle to pick and section this stream of {reality} into significant experiences we supply ahead in life?

The NTNU researchers have discovered a “leaping” reply.

The researchers examined part of the mind’s reminiscence system referred to as the lateral entorhinal cortex (LEC). This space supplies necessary enter that helps generate our sense of time throughout experiences and recollections.

A brand new know-how referred to as Neuropixels has made it potential to document from hundreds of mind cells on this space concurrently.

“What we discovered was that the mind cells work collectively to create a sign that consistently drifts in a sample that by no means repeats itself—not even throughout sleep. This drift is not pushed by what we do or see, however is an inherent property of the community,” stated Moser, professor of neuroscience on the NTNU Kavli Institute.

It is as if this mind space is hardwired particularly to seize new sensations and experiences.

The mind creates bookmarks

“When one thing necessary, sudden, or significant occurs—for instance, a reward, a brand new place, or a shock—this sign makes a sudden leap earlier than persevering with its quiet drift. These jumps mark the start and finish of an {experience},” stated Ben Kanter, first creator of the research.

The researchers use the analogy of beads on a string as an example how our sense of time works. The string represents our subjective {experience} of time, which normally drifts easily ahead. But when one thing necessary occurs, the sign jumps. Moser demonstrates this by lifting the string upwards, and May-Britt attaches a paperclip at that spot. The paperclip marks the beginning of a brand new {experience}—a type of bookmark within the mind.

The researchers recorded exercise within the lateral entorhinal cortex (LEC), the a part of the mind that contributes to our sense of time. They discovered that:

• LEC exercise drifts slowly ahead with out ever repeating itself, no matter what the animal is doing—together with throughout sleep.
  • When one thing necessary or stunning occurs, the sign makes a sudden leap. Activity will increase quickly initially of a brand new occasion earlier than settling again to baseline.
  • These jumps create distinctive neural “barcodes” for every {experience}, enabling the mind to retailer and retrieve recollections.

After that, the sense of time continues its quiet drift, with occasion after occasion threaded onto the string within the right order, like beads on a necklace. In this manner, the jumps divide the continual stream of sensory data into distinct and significant experiences, organized within the sequence they really occurred.

“These jumps give every {experience} a novel neural signature—a bookmark, like a barcode within the mind—making it potential to retailer experiences as recollections and retrieve them later,” Kanter stated.

Time flips our recollections

The study additionally explains why time feels so totally different within the brief time period in comparison with in reminiscence.

“A boring hour can really feel lengthy whereas it is occurring, nevertheless it leaves behind few recollections and thus feels quick on reflection. When we’re having enjoyable, time flies—it feels quick within the brief time period, however we find yourself with many wealthy recollections, making it really feel as if we skilled greater than the precise time would recommend,” stated May-Britt Moser, professor of neuroscience at NTNU’s Kavli Institute.

“The mind does not measure skilled time itself, however experiences. The extra particulars and occasions we retailer, the richer and longer time seems in our reminiscence,” stated Edvard Moser.

In different phrases, it’s our experiences and recollections that create our sense of time.

An necessary piece within the Alzheimer’s puzzle

The findings might also have main implications for understanding dementia.

“Alzheimer’s illness usually begins within the lateral entorhinal cortex—exactly where the sense of time is created,” stated May-Britt Moser. “When the cells within the LEC die, it turns into tougher to arrange recollections and perceive the sequence of occasions.”

She illustrates this by selecting up scissors and reducing the bead string Edvard is holding. The organizing thread of time is severed, and the beads—the occasions—spill out in disarray, with out construction.

“Our objective is to know how a wholesome mind organizes time and recollections. If we succeed, we might be able to develop strategies to detect Alzheimer’s earlier and cease cell demise earlier than the illness causes an excessive amount of harm,” she says.

At the Okay.G. Jebsen Center for Alzheimer’s Disease, neuroscientists at Kavli are collaborating with neurologists at St. Olavs Hospital. They are already utilizing this data to develop biomarkers that may detect the illness early. The final objective is evident: To resolve the Alzheimer’s puzzle—and provides individuals the prospect to maintain their recollections and their lives intact for so long as potential.