That quantification of the lesions as well as the different task measurements came from several decades of work led by two coauthors on the study: Hanna Damasio, Dana Dornsife Chair in Neuroscience at the University of Southern California (USC); and Daniel Tranel, professor or neurology and psychology at the University of Iowa.
"The patterns of lesions that impair specific tasks showed a very clear separation between those regions of the frontal lobes necessary for controlling behavior, and those necessary for how we give value to choices and how we make decisions," says Tranel.
Ralph Adolphs, Bren Professor of Psychology and Neuroscience at Caltech and a coauthor of the study, says that aspects of what the team found had been observed previously using fMRI methods in healthy people. But, he adds, those previous studies only showed which parts of the brain are activated when people think or choose, but not which are the most critical areas, and which are less important.
"Only lesion mapping, like we did in the present study, can show you which parts of the brain are actually necessary for a particular task," he says. "This information is crucial, not only for basic cognitive neuroscience, but also for linking these findings to clinical relevance."
For example, several different parts of the brain might be activated when you are making a particular type of decision, explains Adolphs. If there is a lesion in one of these areas, the rest of your brain might be able to compensate, leaving little or no impairment. But if a lesion occurs in another area, you might wind up with a lifelong d
|Contact: Brian Bell|
California Institute of Technology