A breakthrough in understanding the brain’s noradrenaline (NA) system has been achieved by a team of researchers. This system, which has long been targeted for the treatment of attention-deficit/hyperactivity disorder (ADHD), depression, and anxiety, has been a challenge to study in humans. However, the researchers have developed a groundbreaking methodology that allows for real-time chemical activity to be recorded from standard clinical electrodes used for epilepsy monitoring.
Traditionally, studying brain function in humans has required the insertion of electrodes into the brain. This approach has limitations and is not feasible for many patients. The researchers took a different approach by using electrodes that were already in place for medical procedures. They used carbon-fiber electrodes in awake patients receiving deep brain stimulation surgery for Parkinson’s disease or other disorders. This novel technique demonstrated that electrochemistry can be performed using existing clinical electrodes, providing an opportunity to observe previously unseen brain activity.
The electrodes used in the study were placed in the amygdala, a region of the brain involved in emotional processing and heavily influenced by NA signals. The NA system originates in the locus coeruleus (LC), a small midbrain nucleus, and has been a target for developing medications to address conditions like ADHD, depression, and anxiety. However, direct recordings of the NA system in humans have been lacking, hindering our understanding of its role in health and disease.
During the study, the researchers asked three patients to view neutral and emotionally charged images. This allowed them to observe how the NA system responds to different emotional states. They found that the levels of NA correlated with emotional intensity, particularly when unexpected images were encountered. These findings highlight the significance of the NA system in conditions like ADHD.
This research has been hailed as groundbreaking and a significant technical advancement in our ability to understand human brain activity. It not only provides insights into the brain’s chemistry and its implications for various medical conditions but also demonstrates a new capability to gather data from the living human brain. The techniques developed in this study will have wide-ranging applications and contribute to our efforts to understand the functions of human brain circuits.