They also saw that the difference of power increase between trained and untrained regions of the visual cortical area was correlated with each individual's performance improvement on the task.
The results are novel, in large part because the scientists employed a unique blend of measurement technologies including magnetic and electronic encephalography, magnetic resonance imaging and polysomnography to measure the brainwaves in specific brain regions with millimeter and millisecond precision during distinct phases of sleep.
The repeated significance of sigma oscillations, known as sleep spindles, in both the visual task and the motor task may be important in figuring out a broader picture of how the brain consolidates learning during sleep, the researchers said. They did not, however, see the same uptick of delta frequency power that they saw in their study of the motor task.
Neuroscientists believe the two frequency bands play different roles. The sigma frequency is associated with internal workings of a brain region, while delta is associated more with inter-region communication.
"So far we are thinking that the sigma band is used commonly during learning-related jobs, but not necessarily the delta bands," said Yuka Sasaki, associate professor (research) of cognitive, linguistic, and psychological sciences.
With more to learn, both awake and asleep, their studies continue in their sleep lab at Brown.
|Contact: David Orenstein|