New study reveals hidden patterns in brain memory

Why do we remember some experiences for a lifetime while forgetting others quickly?

A new study by researchers from Aarhus University and Oxford University sheds new light on this mystery. The research team has investigated how different brain regions work together when we recognize sounds and recall past experiences.

The method used in the study made it possible to measure irreversibility in brain activity—essentially identifying how certain connections between regions play a crucial role in cognition and memory by not simply operating as a back-and-forth exchange.

The study is based on data from magnetoencephalography (MEG), where participants recognized musical sequences that they previously learned. The results showed that certain brain regions—especially those involved in cognition and sensory processing—exhibited a high degree of irreversibility.

This finding indicates that the brain does not merely function through simple two-way communication between paired regions but instead operates as a complex network of larger, cooperating units.

“This result gives us a unique opportunity to understand how brain regions work together. We can now see that the connections crucial for memory are not just simple links but rather a complex hierarchy of interactions,” explains Associate Professor Leonardo Bonetti from the Department of Clinical Medicine at Aarhus University.

A breakthrough in brain research

At the core of this discovery is a new computational method called Directed Multiplex Visibility Graph Irreversibility (DiMViGI). This technique allows researchers to analyze brain dynamics in an entirely new way by detecting irreversible patterns in complex interactions across different levels.

Unlike previous methods that only measured global brain activity, DiMViGI makes it possible to pinpoint how specific brain regions interact over time, revealing a structured, non-equilibrium organization of brain function. By applying this method to MEG data, researchers have gained deeper insights into how cognition and memory emerge from complex network interactions in the brain.

“Physics and neuroscience have long influenced each other, and this study is an exciting example of that relationship. By applying tools from statistical physics, we’ve uncovered new insights into how brain regions work together to support memory,” said Ramón Nartallo-Kaluarachchi, a DPhil candidate at the University of Oxford’s Mathematical Institute.

This innovative approach opens new doors in neuroscience, offering a powerful tool to study brain function, memory, and potentially even diseases where brain network communication is disrupted, such as Alzheimer’s disease.

New understanding of brain development

Although the study is based on advanced neuroscience, it also has practical implications. Our memory and perception are not static but are shaped by the brain’s ever-changing network of connections.

This knowledge may help us better understand how the brain changes with age, sleep, and diseases such as Alzheimer’s.

“We are beginning to understand how our brain functions as a dynamic system that constantly adapts to new information. This knowledge can help us explain why, for example, we recognize a melody we haven’t heard in years or why some memories remain strong throughout life,” says Leonardo Bonetti.

Major prospects for the future

The method behind the study can also be applied to other cognitive functions to investigate whether the same patterns emerge in different types of thinking and learning.

Additionally, it may be useful for understanding neurological diseases where disruptions in brain networks play a role.

“The future of this research looks exciting. We can imagine that this method could also be used to study how the brain develops over time or how it is affected by disease. It provides us with a new approach to understanding cognition at a deeper level,” says Bonetti.

Behind the research – more information

Study type: Basic research

Collaborators: The study was carried out through a strong collaboration between the Center for Music in the Brain, Aarhus University and the Centre for Eudaimonia and Human Flourishing and the Department of Mathematics, University of Oxford, with additional contributions from Pompeu Fabra University.

External funding: The key foundations are the Danish National Research Foundation, Lundbeck Foundation and Carlsberg Foundation

Conflicts of interest: None

Linkt to scientific article: https://www.pnas.org/doi/10.1073/pnas.2408791122

Contact

Associate Professor Leonardo Bonetti
Aarhus University, Department of Clinical Medicine - Center for Music in the Brain
Phone: +45 81 94 91 90
leonardo.bonetti@clin.au.dk