Scientists at Carnegie Mellon University have developed a new electroencephalography (EEG) system capable of recording brain signals at an unprecedented spatial resolution. The so-called “super-Nyquist density” EEG was compared to four different conventional “Nyquist density” EEGs when tried on 14 volunteers. The new system was able to record a lot more data from the visual cortex, and so revealed a lot more of what is going on inside the brain. The technology should have significant impact on neuroscience research, as it will help scientists understand the brain better, and also on a variety of medical applications such as identifying the sources of epileptic seizures.
Traditional EEGs work under an assumption of a fundamental limit of signal data density known as Nyquist-Shannon sampling theorem. That is why they all have electrodes positioned about eight to twelve inches (20 – 30 cm) apart. The new EEG is a 128 electrode array, but the electrodes are positioned on the scalp closer to each other, approximately 6 inches apart (14 cm). The researchers had clues that there might be more data available when positioning the electrodes closer to each other, particularly in specific situations, so they went ahead and tried doing so in a set of cases.
The results showed that indeed, when the brains of the volunteers were stimulated using visual signals, the new EEG system was able to capture more neural information. The researchers hope to better understand why this is the case, while others that rely on EEG can hopefully begin trying to obtained better data in their own experiments.
Study in journal Scientific Reports: Very high density EEG elucidates spatiotemporal aspects of early visual processing…/a>
Via: Carnegie Mellon…