New Precision Technology Helps Rewire Brain Circuits

A groundbreaking study reveals a precise new way to rewire brain circuits — opening the door to potential treatments that go beyond the traditional approaches of medication or external stimulation and bypass damaged neural connections.

Elizabeth Ransey, an assistant professor in Carnegie Mellon University’s Department of Biological Sciences, played a central role in developing the technology, called LinCx, which allows scientists to create highly specific electrical connections between select neurons. The research, conducted at Duke University School of Medicine in the lab of Dr. Kafui Dzirasa, was published in Nature in May.

“This study points toward a future where engineered gap junctions can be used to control and interrogate cell-to-cell communication across the brain, heart and other organ systems in mammals,” Ransey said. “Here, we have begun to explore that exciting possibility by using them to precisely edit mammalian neural circuits.”

Broken and disrupted brain circuits contribute to many neurological and psychiatric disorders. Instead of repairing faulty connections, LinCx introduces a new kind of biological “wire,” an engineered electrical bypass that strengthens communication between targeted neurons without altering existing synapses.

“By introducing a way to plug in new electrical connections with cellular level precision, our study marks a major step forward in the ability to edit brain circuitry and understand how neural networks give rise to behavior,” said Dzirasa, the A. Eugene and Marie Washington Presidential Distinguished Professor of Psychiatry & Behavioral Sciences, Behavioral Medicine & Neurosciences at Duke University.

Precision engineering

Ransey, who completed this work as a postdoctoral researcher at Duke University, brings a background in protein biochemistry and engineering. During graduate school, she became interested in protein structure and how protein complexes influence cell behavior, drawing her to the challenge of reprogramming neural circuits.

“The goal sounded almost simple,” she said. “Make two proteins connect only to each other. But of course, it was not at all. That challenge is really what drew me in.”

The project, which spanned years and multiple experimental systems, sits at the intersection of protein engineering, cell biology and neuroscience.

The LinCx system builds on gap junctions, natural protein channels that allow neighboring cells to directly exchange electrical and chemical signals. However, natural gap junctions are difficult to control because they form broadly and unpredictably across cells.

Ransey and colleagues overcame this limitation by creating a paired, two-component system: two modified proteins that selectively dock with one another while avoiding interaction with native brain proteins.

“One key finding was that this kind of specificity can actually be engineered,” she said, adding that the largely system ignores native mammalian proteins, so the researchers could control connections without disrupting existing networks.

Laboratory screening — including a newly developed fluorescence-based assay — identified highly specific protein pairs capable of reliably transmitting electrical signals between cells.

A major breakthrough came when the team showed that LinCx works in living animals. After validating the system in human-derived cells and frog oocytes, the researchers tested it in worms and mice.

Across these models, adding engineered connections changed how neural circuits functioned and even altered behavior. In worms, the new connections shifted temperature-seeking behavior. In mice, the targeted electrical links reshaped brain-wide activity patterns and produced measurable effects on social interaction and stress responses.

“Showing that the system could function in vivo and influence circuit function and behavior was a major breakthrough,” Ransey said.

A new way to study and design communication

The work addresses a long-standing limitation in neuroscience. Existing tools, such as drugs, electrical stimulation and optogenetics, tend to affect large groups of cells rather than precise connections between defined cell types.

LinCx introduces a fundamentally different capability: controlling communication itself.

“We can specify both sides of the connection,” Ransey noted. “That gives us much more precision than approaches that activate one population and indirectly affect everything downstream.”

The approach could enable scientists to design cells that communicate in predictable programming ways, improving the development of lab-grown tissues and enabling new kinds of biological systems that function more like engineered circuits.

Most importantly, the technology suggests a new strategy for treating disease. Rather than trying to repair damaged connections, researchers could create new pathways to restore communication. For conditions where disrupted connectivity is central — such as depression, autism or neurodegenerative diseases — LinCx could offer a more effective way to improve brain function.

The team’s next step is to test whether engineered connections can compensate for lifelong genetic disruptions in neural circuits — raising the possibility of using such biological “bypasses” to restore brain function.

Funding for the work was provided by the Burroughs Wellcome Fund, the Ernest E. Just Life Science Institute, The Hartwell Foundation, Hope for Depression Research Foundation, Howard Hughes Medical Institute and the National Institutes of Health.