An international team of researchers has provided valuable insights into the brain's noradrenaline (NA) system, which has been a longtime target for medications to treat attention-deficit/hyperactivity disorder, depression, and anxiety.
Equally important beyond the findings is the groundbreaking methodology that the researchers developed to record real-time chemical activity from standard clinical electrodes which are routinely implanted for epilepsy monitoring.
Published online in the journal Current Biology on Monday (Oct. 23), the research not only provides new insights into the brain's chemistry, which could have implications for a wide array of medical conditions, it also highlights a remarkable new capacity to acquire data from the living human brain.
"Our group is describing the first 'fast' neurochemistry recorded by voltammetry from conscious humans," said Read Montague, co-corresponding and senior author of the study, the VTC Vernon Mountcastle research professor at Virginia Tech, and director of the Center for Human Neuroscience Research and the Human Neuroimaging Laboratory of the Fralin Biomedical Research Institute at VTC. "This is a big step forward and the methodological approach was implemented completely in humans – after more than 11 years of extensive development."
About the method
Voltammetry techniques for making real-time electrochemical readings in rodents and other laboratory models have yielded deep insights into brain function for about 30 years, but there was no clear path to use the techniques in humans, because they require electrodes to be inserted into the brain.
"Instead, we focused on what's already being used in patients for medical procedures," said Montague, who is also a professor in the Department of Physics at the Virginia Tech College of Science and in the Department of Psychiatry and Behavioral Medicine at the Virginia Tech Carilion School of Medicine. "When are surgeons already putting a wire in someone's brain? And could we design a method to piggyback on that?"
The team's initial approaches required the insertion of exclusive carbon-fiber electrodes designed at the Fralin Biomedical Research Institute into awake patients receiving deep brain stimulation surgery for Parkinson's disease or other disorders.
The research team has now demonstrated that electrochemistry can be performed with electrodes that are already in place and in standard clinical use, opening a window to never-before-seen brain activity.
About the noradrenalin system
The electrodes were in the amygdala, a brain region deeply intertwined with emotional processing and profoundly influenced by NA signals.
The NA system originates in a small midbrain nucleus known as the locus coeruleus (LC), and it has long been a focal point for developing medications aimed at addressing conditions like ADHD, depression, and anxiety.
