Synchronous bursts of activity help the brain avoid losing information

Working memory is essential for everyday tasks: for example, to follow instructions, navigate an unfamiliar place, or remember the details of a conversation. Previously, the activity of so‑called “ripples” — high‑frequency brain waves — was primarily associated with the formation of long‑term memory. However, it remained unclear whether these waves help coordinate neural activity over long distances during active thinking. A new study shows that they may indeed serve as a mechanism for long‑range neural communication, enabling the brain to integrate information.

The study analyzed recordings of brain activity from 35 patients who had previously had electrodes implanted to monitor epilepsy. The participants were shown one or three images and asked to hold them in memory for a short time, and then determine whether a test image matched one of the original ones. The researchers monitored activity in several brain regions associated with memory and cognitive processes to identify coordinated patterns of neural activity.

It turned out that “ripple”‑type oscillations intensified at all stages of the working memory task. When such waves occurred simultaneously in different areas of the brain, the likelihood of simultaneous activation of neurons in these zones increased by approximately 30%, even if the distance between the areas reached 220 millimeters. At the same time, the degree of coordination increased as the memory load increased. At the stage of information retrieval (when the brain accesses stored data), synchronous “ripples” helped recreate the same patterns of neural activity that were used during the initial formation of the memory.

These data suggest that “ripples” serve as a kind of synchronizer for distributed brain networks, ensuring coordinated information processing. The discovery may help to better understand how neural networks responsible for memory function, both in normal conditions and in pathologies. In particular, it provides a tool for distinguishing healthy cognitive signals from the abnormal high‑frequency activity characteristic of neurological diseases.

The results are particularly important for studying conditions in which the connectivity of brain networks is disrupted, such as Alzheimer’s disease or attention deficit hyperactivity disorder (ADHD). Understanding the role of “ripples” in maintaining working memory may in the future contribute to the development of new approaches to the diagnosis and treatment of such disorders.