Surprisingly Complex Waves Reveal the Brain’s Inner Workings

The brain operates using electrical activity to perform everyday tasks like navigation, memory, and decision-making. About half of the brain's energy is spent maintaining electrochemical gradients in neurons, allowing them to fire rapidly when needed. This electrical activity creates waves that travel across brain regions, similar to waves in a stadium where spectators raise their arms in sequence. Traditionally, these waves were thought to be simple oscillations, like the sound of an engine running, but new research shows they are far more complex and play a central role in brain function. Earl K. Miller, a cognitive neuroscientist at MIT, notes that recent work is shifting the understanding of these waves from being mere background noise to being a fundamental way the brain processes information.

Neuroscientists have long measured brain waves using electrodes on the scalp, identifying oscillations such as alpha, beta, gamma, and theta waves, measured in hertz (cycles per second). These waves change with attention, memory, and sleep. However, electrodes on the scalp provide limited detail. Joshua Jacobs and his team at the University of Chicago use intracranial brain recordings, placing around 100 electrodes inside the brain of epilepsy patients to capture high-resolution data. In a 2026 study in Nature Communications, they observed diverse wave patterns, including source waves that spread from one location, sink waves that converge on a spot, and spiral waves that rotate like hurricanes. These patterns varied depending on the task, such as verbal memory or spatial navigation, suggesting waves help the brain reorganize in real time to meet behavioral demands.

In a 2024 study in Nature Human Behavior, Jacobs and Uma Mohan observed waves traveling in opposite directions across the brain's cortex during memory tasks. Waves moved from the back of the brain (visual regions) to the front (prefrontal cortex) when forming memories from visual input. Conversely, waves traveling from front to back might indicate recalling stored memories. Mohan explained that these waves could help the brain switch between encoding and recalling memories rapidly, depending on what the brain needs to support at a given moment. This suggests that wave direction reflects the flow of information and the brain's current cognitive focus.

The 2026 research by Jacobs and Anup Das revealed that brain waves can form more complex patterns than previously thought. In experiments involving verbal and spatial memory tasks, they observed concentric waves, like ripples from a pebble dropped in water, and rotating spiral waves, similar to hurricanes or flushing toilets. These spiral waves appeared more frequently during complex spatial tasks, suggesting they may be better suited for intricate cognitive behaviors. Jacobs noted that these patterns were only visible when analyzing groups of electrodes separated by specific distances, indicating that earlier studies may have missed the full complexity of brain waves due to limited electrode placement.

Bard Ermentrout, a mathematical biologist at the University of Pittsburgh, has studied similar wave patterns in mice. He proposed that simple planar waves observed in the past might be part of larger, more complex patterns, such as the outer arms of a hurricane surrounding its eye. Ermentrout co-authored the 2026 Nature Communications paper and suggested that the brain's wave patterns could be more dynamic and flexible than previously assumed. Jacobs acknowledged that current data is limited to brain regions where electrodes are implanted for epilepsy treatment, meaning the true ubiquity of these patterns remains unknown.

Some scientists believe traveling waves in the brain's local electric field help coordinate activity between regions. Earl K. Miller argues that these waves provide a dynamic, flexible layer of organization that shifts on the same timescale as behavior, unlike stable neural connections. He described neurons as being on the edge of firing, like Humpty Dumpty on a wall, and suggested that oscillating electrical activity can alter the likelihood of neurons firing in the future. Miller proposed that waves might play roles in sensory processing, prediction, and modulating neuronal excitability. However, not all researchers agree; György Buzsáki of NYU argues that waves are merely a reflection of synaptic activity and do not directly contribute to information processing.

In June 2026, a study in Science by Zhiwen Ye and Nicholas Steinmetz observed rotating waves in the brains of mice, mirrored and synchronized between the left and right hemispheres. The researchers found that neurons in the somatosensory cortex, which integrates sensory and motor information, were wired in a spiraling arrangement, potentially facilitating these wave patterns. Ye suggested that if these waves were not important, the brain would not invest resources in wiring neurons this way. This finding supports the idea that wave patterns are a fundamental feature of brain function, not just an epiphenomenon.

Lyle Muller of the University of Texas at Dallas and John Reynolds of the Salk Institute proposed in a September 2026 Neuron review that traveling waves in the visual cortex could help the brain predict upcoming sensory information. They described how evolving wave patterns carry information about past and current experiences to aid short-term predictions. This suggests that waves may help the brain compress noisy sensory input and anticipate future events, enhancing efficiency in processing the environment. The authors drew on decades of neuroscientific findings to argue that these waves are integral to cognitive functions.