Yale Team Uncovers Origin of Gamma Brain Waves in Thalamus-Cortex Interaction

A Century-Old Neuroscience Puzzle Solved

For over a hundred years, scientists have been tracking the brain’s rhythmic electrical patterns without fully understanding where they come from or exactly what they do. Now, according to research published in Nature, Yale University neuroscientists have cracked one of neuroscience’s enduring mysteries by pinpointing the origin of gamma waves and linking them directly to behavior.

The breakthrough came from an unexpected direction. Senior author Jessica Cardin, PhD, had actually stepped away from gamma wave research years earlier, considering the “perfect experiment” to test their function nearly impossible to achieve. “When I started my own lab, I thought we’d never work in this area,” Cardin told reporters. That changed when postdoctoral researcher Quentin Perrenoud presented data suggesting gamma waves might predict behavior—a finding that sent the team down a new investigative path.

Mapping the Brain’s Rhythm Section

What makes this discovery particularly significant is the technical innovation behind it. The Yale team developed a new method called CBASS (Clustering Band-limited Activity by State and Spectrotemporal feature) that allowed them to measure gamma activity with unprecedented precision. Instead of treating these brain waves as continuous oscillations, CBASS captures them as discrete events—individual peaks and troughs that occur in unpredictable bursts.

“It allows us to get very fine timing and to clearly identify these short events,” Cardin explained in the study. “That means we can map the events in the brain to the behavior of the animal with more precision than we’ve ever had before.”

The enhanced resolution revealed something surprising about gamma’s origins. For decades, neuroscientists had debated whether gamma waves were generated in the cortex or inherited from the thalamus. According to the Yale findings published in Nature, the answer is neither—and both. “Our data suggest both are wrong, and that this activity arises due to an interaction between the thalamus and the cortex,” Cardin noted.

From Laboratory to Real-World Impact

The implications extend far beyond basic neuroscience. When researchers disrupted thalamus-to-cortex signals in mice performing visual tasks, the animals’ performance plummeted. Even more strikingly, when scientists artificially generated gamma activity and played it back into mice brains, the animals were tricked into thinking they’d seen visual stimuli that weren’t actually present.

This demonstrates that gamma waves aren’t just background noise—they’re actively involved in processing sensory information and shaping behavioral responses. That connection becomes particularly important when considering that gamma activity is known to be altered in conditions ranging from schizophrenia and bipolar disorder to Alzheimer’s disease.

Cardin’s lab is now exploring whether gamma patterns could serve as early biomarkers for neurodegenerative diseases. “We’re starting to look at how neuromodulatory signals are associated with these gamma events,” she said, noting that acetylcholine and norepinephrine—key signaling molecules linked to cognition—are known to regulate these brain rhythms and are depleted in conditions like Alzheimer’s.

Building on this discovery, the research could eventually lead to diagnostic tools that detect neurological disorders earlier than current methods allow. For a scientific question that’s persisted for over a century, that represents remarkable progress in surprisingly little time.

Research funding was provided by the National Institutes of Health, with additional support from the McKnight Foundation, the Kavli Institute of Neuroscience, and the Brain and Behavior Research Foundation.