For decades, the brain's electrical activity has been read as travelling waves: ripples of voltage sweeping back and forth across the cortex, often treated as little more than the sound of the engine running. New research suggests that picture is incomplete — and that the waves may be a central motif of how the cortex processes information.
Writing in Nature Communications in April 2026, a team including Joshua Jacobs and Anup Das of the University of Chicago used intracranial electrodes — roughly 100 per patient, implanted to locate the source of epileptic seizures — to record high-resolution activity while volunteers performed verbal and spatial memory tasks. Alongside the familiar planar waves, they found two classes of patterns previously unseen in awake humans: concentric waves that emanate from, or converge on, a single patch of cortex, and rotating spiral waves that sweep clockwise or counterclockwise like a hurricane.
The shape tracked the task. Rotating waves appeared more often during the complex spatial navigation task, while the verbal memory task produced simpler structures. "Maybe the planar waves are just the outer arms, where you're missing the eye of the storm," said co-author Bard Ermentrout, a mathematical biologist at the University of Pittsburgh. "In a hurricane you only feel the wind going in one direction. You don't know that it is spinning unless you're right there by the eye."
The result builds on earlier work. A 2024 paper by Jacobs and NIH neuroengineer Uma Mohan described waves running front-to-back or back-to-front across the cortex during encoding and recall, effectively showing the direction in which information propagates. A June 2026 study in Science by Zhiwen Ye of the Shenzhen Medical Academy of Research and Translation and Nicholas Steinmetz of the University of Washington observed the same hurricane-like waves in mice — mirrored and synchronized across the two hemispheres, with axons in the somatosensory cortex wired in spirals that could generate them. "If they are not important, why would the brain try to wire these cells in this way?" Ye asked.
In a September 2026 review in Neuron, Lyle Muller of the University of Texas at Dallas and John Reynolds of the Salk Institute argue that travelling waves in visual cortex help predict upcoming sensory information, carrying the recent past alongside the present to anticipate what comes next.
The interpretation is contested. György Buzsáki, a systems neuroscientist at NYU, holds that the waves are a reflection of synaptic computation rather than a channel of their own: more synchronous neurons simply produce a stronger field. Others disagree. Earl Miller of MIT describes cortical neurons as teetering on the edge of firing, with the oscillating field nudging them one way or the other, and says the emerging evidence has moved the field from "are they relevant?" to "this is a major motif of how the cortex processes information."
One limitation is built into the method: data comes only from electrode placements chosen for epilepsy treatment, so the true prevalence of these patterns remains unknown.
