Neuromodulation devices can treat disorders by electrically stimulating the brain. But researchers haven’t been able to actually see how this approach is affecting the neurons involved in the process.
University of Wisconsin-Madison Associate Professor of biomedical engineering Kip Ludwig is among the authors of a new paper in Neuroscience Research that sheds light on the underlying neural process in neuromodulation and the effects of different stimulus parameters. Takashi D. Y. Kozai, an assistant professor of bioengineering at the University of Pittsburgh, led the study.
Previous studies had generated conflicting results on which parts of the neural circuit were activated when stimulated by an electrode: the somas of the neurons close to the electrode or those farther away whose axons ran by the electrode. By using Kozai’s optical techniques—a novel use of two-photon microscopy—the researchers were able to view all the circuits in real time and show that both prior claims were true, depending on stimulation frequency and time span.
“This is important for understanding how these therapies work, as the electrical activation nearby the electrode changes over time as you stimulate,” says Ludwig. “You need this knowledge to know how you would stimulate over time to activate different parts of the circuit deliberately to treat aberrant circuit behavior that is the hallmark of epilepsy, Parkinson’s disease and essential tremor.”