The brain's frontal lobe may be organized in a front-to-back continuum, with concrete decision-making occurring toward the back of the lobe and abstract thought toward the front, according to a recent study conducted by Assistant Professor of Cognitive and Linguistic Sciences David Badre.
Badre was the lead author of the study conducted at the University of California, Berkeley, where he was a postdoctoral fellow before coming to Brown in 2007, according to a March 1 Brown press release. "It tells us more about how the brain works and how it's organized," he told The Herald.
The frontal lobe affects human behavior by controlling decision-making, planning and reasoning.
According to the press release, the study, published in the March 1 issue of Nature Neuroscience, is among the first to show that different areas of the frontal lobe correspond with varying degrees of abstract thought.
In addition to furthering understanding of human thought, these findings could have a range of applications, including advances in the treatment of strokes.
The study was conducted over the course of two years because of the nature of patient studies, which are often lengthy processes, Badre said. He and his colleagues studied patients who had a suffered a stroke at least six months before being tested. The 11 subjects - seven men and four women - ranged from 45 to 73 in age and had suffered damage to various areas of their frontal lobes as a result of their strokes.
The patients performed four "response selection tests" that required the press of a finger in response to computerized cues. One such test, outlined in the University release, functioned through responses to colors. Red would prompt the subjects to press with their index finger, while blue would prompt the middle finger. By increasing alterations between fingers, the test became increasingly complicated.
Badre said the other tests were more complex in format but still consisted of the same idea of progressing from simple to complex decisions. He said abstract thought is demonstrated when subjects have to make decisions based on other previous decisions. "If there is damage in a given spot, it will affect all higher (decision-making) functions but not lower functions," Badre said in the press release.
In the study, Badre and his colleagues found that damage to the anterior frontal lobe affected frontal abstract thought but left concrete decision-making, located in the back of the lobe, intact.
To account for variance between subjects, such as their range of ability to perform such tests before suffering a stroke, according to Badre, researchers employed "within-subject comparison" to use subjects as their own controls. "All these little differences average out at the group level," he said.
