Finding focus

Having trouble paying attention? MIT neuroscientists may have a solution: turn down your alpha brain waves. In a recent study, subjects who used neurofeedback to suppress alpha waves in one hemisphere of their parietal cortex were able to pay better attention to objects that appeared on the opposite side of their visual field.

“There’s a lot of interest in using neurofeedback to try to help people with various brain disorders and behavioral problems,” says Robert Desimone, director of MIT’s McGovern Institute for Brain Research, who led the study. “It’s a completely noninvasive way of controlling and testing the role of different types of brain activity.”

Subjects were asked to use mental effort to increase the contrast in a grating pattern at the center of a screen while being scanned with magnetoencephalography (MEG), which reveals brain activity with millisecond precision. The greater the asymmetry between alpha levels in the left and right hemispheres of the parietal cortex, which is involved in attention, the more visible the pattern became, offering real-time feedback.

Although subjects were not told what was happening, after about 20 trials they were able to increase the contrast. The MEG results indicated they had done so by dampening alpha waves in one hemisphere. Experimental tasks they performed after the training showed that they paid more attention to activity in the side of the visual field opposite that hemisphere.

“After the experiment, the subjects said they knew that they were controlling the contrast, but they didn’t know how they did it,” says McGovern Institute postdoc Yasaman Bagherzadeh, the study’s first author. She believes the feedback enabled them to learn by practicing.