In order to concentrate on something, your brain also has to perform the task of ignoring other things. But just how the brain achieves such “optimal inattention” has been a subject of debate among scientists.
Study participants were told they would feel a brief tap on the left middle finger or the left big toe.
In some cases they were then told to report only stimuli felt on the foot and to disregard what they might feel on their hand.
In other cases they were told to attend to or report sensations only in the hand and to ignore those in the foot.
Researchers measured the power and timing of different brain wave frequencies in various brain regions. They were mainly interested in looking at the synchronization of brainwaves between two regions.
The first area was the part of the somatosensory cortex that processes touch in the hand. The second was the right inferior frontal cortex (rIFC), a part of the brain known to govern suppression of attention and action.
Synchrony between Brain Regions
The researchers observed noteworthy patterns of synchrony between regions.
Looking at the synchronization between the somatosensory cortex’s hand region and the rIFC, they saw significant increases when people were told to pay attention only to sensations in the foot, compared to when they were told to attend to sensations only in the hand.
A pattern emerged in the fraction of a second after people were told to focus their attention on the coming sensation, but before the stimulation actually occurred.
In that small time period, alpha wave synchrony at 7-14Hz was much higher between the part of the somatosensory cortex responsible for the hand, and the rIFC in people focusing on the foot than in people focusing on the hand. This pattern aligns with the brain getting ready to suppress or ignore sensations felt in the hand.
The researchers also saw a considerable disparity between alpha rhythm synchrony between the IFC on the left side of the brain and the somatosensory cortex pertaining to the hand, which they speculate could be related to formulating the rules about whether suppress or attend to sensations.
Somatosensory Cortex Alpha and Beta Rhythms
Previous work done by the team showed that people can learn, through mindfulness meditation, for example, to manipulate their alpha rhythms in the somatosensory cortex as they switch their attentional focus.
The new results expand those findings by describing how alpha and beta rhythms appear to connect the somatosensory cortex to the frontal cortex to coordinate the multistep process of taking attention away from, and then ignoring, a sensory stimulus.
Study co-senior author Catherine Kerr said about the research:
This is part of a really cool effort at Brown to see if you can take pretty high-level cognitive questions, find the relevant areas in the brain, and then figure out how to put that in a context with the underlying neurophysiology, at the level of computational models and animal models. We’re linking different ways of looking at the brain that don’t usually come into dialogue with one another.”
Research results show that mindfulness meditation, also perhaps through the mechanism of throttling attention via control of alpha rhythms, can help people ignore depressive thoughts. Jones and Kerr are also keen to study whether explicit manipulation of alpha and beta waves between a different part of the cortex and the rIFC could give similar relief.