Understanding how the brain works requires more than studying single regions in isolation. The cerebral cortex depends on long-distance connections that link specialized areas into coordinated networks. But scientists have had limited tools for selectively turning these specific connections "on" or "off" in animal models that most closely resemble the human brain.
A new study appearing in Cell Reports Methods describes a new method developed by scientists with the University of Rochester Del Monte Neuroscience Institute to control specific communication pathways in the common marmoset brain, a small primate widely used in neuroscience.
"This study provides us a new way to precisely target how brain regions communicate," said Kuan Hong Wang, PhD , senior author of the study. "Instead of affecting broad areas, we can now control specific pathways, offering a clearer view of the circuits behind complex behavior and brain disorders."
Using a refined viral and light-based technique called optogenetics, the team was able to target only the neurons that connect one brain region to another—and then either activate or silence those same cells on demand. Optogenetics is a method that uses light to control cells genetically modified to respond to it. In neuroscience, it enables researchers to selectively activate or inhibit specific neurons.
These findings represent an important advance because it allows scientists to manipulate individual long-range brain circuits with far greater precision than before. Rather than broadly affecting many nearby cells, researchers can now isolate a single communication pathway within the complex, highly interconnected cortex.
The new method brings us closer to understanding how distributed brain networks support higher-order functions such as perception, decision-making, and social behavior. In the long term, tools like this will also help clarify how disruptions in specific brain circuits contribute to neurological and psychiatric disorders and guide the development of more targeted treatments.
Additional co-authors of the study include Luke Shaw, Krishnan Padmanabhan, Amy Bucklaew, and Jude Mitchell from the University of Rochester. The research was supported with funding from the Del Monte Institute for Neuroscience's Schmitt Program on Integrative Neuroscience, the National Institute of Child Health and Human Development, and the National Eye Institute.
