A team of scientists led by UC Berkeley researchers has identified how different parts of the brain could communicate with one another.
A study published online Monday in the journal Nature Neuroscience describes the physiological process that allows humans to prioritize and complete multiple levels of complex thought. The study was led by Bradley Voytek, an assistant professor in UC San Diego’s cognitive science department who completed the study as a postdoctoral fellow at UC Berkeley, as well as professors Robert Knight and Mark D’Esposito in UC Berkeley’s psychology department.
The study’s participants were patients with epilepsy undergoing electrocorticography, which can locate seizure-prone regions to be removed. The process involves placing electrodes directly on the brain’s surface to measure brain waves.
Voytek said the subjects underwent the procedure for up to two weeks and allowed the researchers a unique opportunity to use electrocorticography, as researchers generally cannot make subjects undergo surgical procedures.
“Normally in neuroscience, we have a trade-off between finding when and where activity is happening in noninvasive methods,” Voytek said. “Whereas if we have invasive (methods), such as when they have surgery … we can reduce that trade-off.”
The study involved testing the patients’ brain activity as they underwent tests of increasingly complex and abstract thinking. Initial tests directed participants to press a button when they saw a light and then added layers of complexity by directing the participants to press a button when they saw a specific color, a specific color and shape, and then a specific color and shape in a particular location.
According to Knight, the researchers tracked levels of high gamma waves — indicating increased activity — and found that as the directions became more complex, more activity was recorded in the anterior part of the frontal lobe, where more abstract thought occurs.
As the directions grew more complex, the connectivity between the anterior and posterior parts of the frontal lobe also increased. The researchers found that brainwaves synchronize momentarily in different parts of the brain at a certain frequency in order to perform a more complex task. In that moment — usually less than a second — neurons in different regions signal one another and transfer information, according to Voytek.
“Right now, this is about understanding the basic science of how your brain works,” Knight said. “The results show the executive control of the interaction between the world and your mind.”
The link between psychiatric disorders and the inability to synchronize brainwaves in different regions of the brain is becoming more apparent, according to Knight, and may be an alternative approach to understanding the causes of such disorders, as opposed to conventional chemical explanations.
Knight said this study, which examined the frontal lobe in response to directions and stimuli, is only one of many exploring the uses of the frontal lobe, which could include social interaction and memory.
Voytek said his lab at UCSD will continue studying the way communication among regions of the brain works.