[ Watch the Video: Are Alpha Waves The Future Of Brain Monitoring? ]
Brett Smith for redOrbit.com – Your Universe Online
Have you ever mistakenly driven through a red light or been unable to see a familiar face in a crowded room?
By using a unique method to test brain waves, researchers from the University of Illinois at Urbana-Champaign and City College of New York have detailed new information on how the mind processes sensory stimuli that may or may not be perceived, according to a new report in the Journal of Cognitive Neuroscience.
“When we have different things competing for our attention, we can only be aware of so much of what we see,” said study author Kyle Mathewson, a postdoctoral fellow in the Beckman Institute for Advanced Science and Technology at UIUC. “For example, when you’re driving, you might really be concentrating on obeying traffic signals.”
Mathewson said this lack of awareness is particularly important when it comes to recognizing an unexpected event – such as a small child running into the middle of the road.
“In the car, we may see something so brief or so faint, while we’re paying attention to something else, that the event won’t come into our awareness,” Mathewson said. “If you present this scenario hundreds of times to someone, sometimes they will see the unexpected event, and sometimes they won’t because their brain is in a different preparation state.”
In the study, the researchers used both electroencephalography (EEG) and the event-related optical signal (EROS) to evaluate 16 participants and chart the electrical and optical information onto individual MRI brain images.
While EEG documents the electric activity across the scalp, EROS uses infra-red light transferred via optical fibers to assess variations in optical properties in the working areas of the cerebral cortex. Due to the skull, EEG sensors are not the best option for determining where brain signals are created. EROS, which investigates how light is dispersed, can non-invasively identify activity inside the brain.
“EROS is based on near-infrared light,” the researchers said. “It exploits the fact that when neurons are active, they swell a little, becoming slightly more transparent to light: this allows us to determine when a particular part of the cortex is processing information, as well as where the activity occurs.”
The researchers’ methods allowed them to chart where suppressing alpha oscillations were coming from. They found that alpha waves are created in the cuneus, which sits an area of the brain that handles visual information.
However, by concentrating interest and being more aware, the executive function of the mind can engage and suppress the alpha waves, thus enabling seeing objects or events that might have been missed in a more laid back mental state.
“We found that the same brain regions known to control our attention are involved in suppressing the alpha waves and improving our ability to detect hard-to-see targets,” said study author Diane Beck, a member of the Beckman’s Cognitive Neuroscience Group.
“Knowing where the waves originate means we can target that area specifically with electrical stimulation” said Mathewson. “Or we can also give people moment-to-moment feedback, which could be used to alert drivers that they are not paying attention and should increase their focus on the road ahead, or in other situations alert students in a classroom that they need to focus more, or athletes, or pilots and equipment operators.”