November 9, 2026
Cognition has to be organized somehow. A new study by researchers in The Picower Institute for Learning and Memory at MIT provides several lines of evidence that the needed organization is implemented across the brain’s frontal cortex by low frequency “theta” waves.
“Theta seems to be this master organizer,” said study senior author Earl K. Miller, Picower Professor in the Department of Brain and Cognitive Sciences at MIT. “Imagine that local brain activity supporting cognition is like individual airport control towers. Theta is the whole air traffic control zone covering hundreds of miles including many airports. It’s the overall infrastructure that ties the system together and organizes it.”
In the study in Cell Reports, animals engaged in cognition by playing a game where they had to remember patterns of dots on a screen and classify them into one of two categories. Meanwhile, Miller’s team, led by postdoctoral Picower Fellow Matthew Broschard, measured the electrical spiking activity of hundreds of individual neurons in three areas of the cortex (the “frontal eye fields,” and two regions of the prefrontal cortex). They also recorded the power of the various frequencies of waves produced during the game by the neurons’ collective, synchronized activity.
What the scientists found after analyzing all this raw data, is that theta waves (4-10 Hz) indicated which information was important at key moments of the game, governed the crosstalk between brain regions, and determined when higher frequency “beta” (15-30 Hz) or “gamma” (40-90 Hz) waves arose in each region.
“An important result was that theta's role in organizing brain activity changed rapidly and depended on what the animal was immediately doing,” Broschard said. “This sort of flexibility is essential for cognition. We constantly need to update what we are attending to and what we are thinking about. These theta waves may be important for rapidly reconfiguring brain activity so that we jump from one thing to the next.”
During the game, neural spiking activity in each of the three regions carried information about various aspects of the game. But notably, in the frontal eye fields (FEF) the phase of theta waves correlated with the spiking that encoded the most pertinent information at the time. For instance, at the moment that the animal had to choose one category vs. the other, spiking information about the choice peaked in the falling phases of theta waves and was weakest in the rising phases. Similarly, when the animal learned the result of the choice (right or wrong), that information was also tightly coupled to theta phase.
“At different times during the task, different information is important,” Miller said. “The information that’s being synchronized to the theta waves is whatever is relevant at the moment. It’s pretty compelling evidence that theta is playing a real functional role.”
Using an analysis technique called Granger Causality, the team was able to measure whether theta waves in some regions influenced activity in the others at key times during the game. The scientists saw several clear patterns of such inter-region influence. For instance, during choice time, theta influence flowed from the two frontal regions back toward the FEF. When the animals learned choice outcomes, the direction depended on whether their answer was right or wrong. If it was incorrect, theta influence flowed forward from the FEF to the frontal regions. But if the choice was correct, the flow remained back from the frontal regions to the FEF.
In another key set of findings, the researchers calculated the coupling of phase and amplitude among theta and higher frequency beta and gamma waves. In numerous studies, Miller’s lab has documented that beta waves appear to control where and when gamma waves can enable information processing in the brain. But that happens at a more local level. The new study shows that while beta holds the strings for gamma, theta holds them for beta.
“Theta phase was coupled to beta amplitude, and beta phase was coupled to gamma amplitude,” the researchers wrote.
The push and pull among the three varied systematically with key moments in the game, for instance when the animals made choices and when they learned the outcomes. And theta’s influenced crossed the regions while beta’s influence over gamma occurred only more locally.
“Theta waves might be especially well-suited to organize brain activity because they oscillate up and down at a relatively slow rate,” Broschard said. “The slower-moving theta waves create a sort of foundation or scaffold that allow faster-moving brain activity to fit inside of. This slower timescale is also ideal for moving information across brain areas and larger distances.”
Overall, the results suggest that theta waves not only control information flow and synchronize neural activity, they do so flexibly as cognitive demands change.
“Theta phase was correlated with spiking information, exhibited directional influences between subareas, and interacted with higher-frequency oscillations,” the authors concluded. “For each of these mechanisms, theta’s role was not static across the trial but shifted dramatically from choices to outcomes. Together, these findings emphasize theta’s role in governing flexible cognition.”
In addition to Miller and Broschard, the paper’s other authors are Scott Brincat and Roman Loonis.
The Freedom Together Foundation, the Army Research Office, the National Institutes of Health, the Office of Naval Research, and the Simons Center for the Social Brain provided support for the research.
