The recordings found a characteristic pattern of activity as the subject paid close attention to the task. High-frequency beta oscillations increased in strength as the subject waited for the relevant instruction, with peaks of activity occurring just before each instructional cue. After receiving the relevant instruction and before the subject moved the cursor, the beta oscillation intensity fell dramatically to lower levels through the remaining, irrelevant instructions.
"Previously, no one has been able to dissociate if beta oscillations are related to attention or to just holding, waiting to initiate movement," Saleh said. "Our results show that these oscillations are tied to the anticipation of oncoming information that is used to make a movement."
The slower delta oscillation also showed a regular pattern as the subject performed the task, adjusting its frequency to mirror the timing of each instructional cue. The authors suggest that this "internal metronome" function may help fine-tune beta oscillations, so that maximum attention is paid at the appropriate time.
"There are lots of stimuli in the world that have rhythm," said Jacob Reimer, post-doctoral researcher at Baylor College of Medicine and another author of the study. "If you're waiting for a signal that is informative, you could pay attention constantly for a long period of time. But if that thing you're waiting for has some rhythmicity to it, maybe a more efficient method is to only pay attention 'on the beat.'"
For example, when someone is playing tennis or basketball, the brain may utilize
|Contact: Rob Mitchum|
University of Chicago Medical Center