“The paper shows how a particular region of frontal cortex is important for the voluntary control of actions.”

The paper reviews two of our empirical papers which show that a particular region of the frontal cortex is necessary for cognitive function in humans. The frontal cortex is still a deep mystery and results that convincingly relate cognitive function to a frontal brain region are rare. Such results are highly encouraging and exciting for researchers who are using other, more correlative, neuroscience methods that cannot demonstrate necessity.

Our discovery is useful to all those researchers interested in the nature of frontal lobe function, in cognitive control, and in disorders of voluntary control such as impulse control (which produce rage, aggression, and substance abuse). The results are based on the methodology of structural MRI, which is not new. However, we have shown how it may be profitably applied in the domain of human patients with lesions in order to identify which areas of frontal cortex are specific to particular cognitive functions.

The paper shows how a particular region of frontal cortex is important for the voluntary control of actions. If this area is damaged, then people have less control over their actions. This represents an important advance in our understanding of human cognitive control, as well as the frontal cortex. In particular, the finding has interesting implications for neurology and psychiatry, especially with respect to attention-deficit/hyperactivity-disorder (ADHD) and other disorders characterized by problems with impulse control. For example, patients with a diagnosis of ADHD are impaired on the same behavioral variables discussed in the paper, and it appears that they may also have damage to this same brain region. These findings could put neuropsychiatric research on a firmer footing by pointing to this particular frontal brain region as a clue in understanding the development, genetics, and treatment of various impulse control disorders. The finding also has repercussions for understanding how variations of impulsivity and other personality traits in the normal healthy population relate to the function and structure of the brain.

I became intrigued as to how mental processes relate to brain regions and systems in both health and disease. As a graduate student in Cambridge, England, I seized the opportunity to study patients with frontal lobe damage. Each patient had received a structural MRI scan, and so we could localize the lesion fairly precisely. I was lucky to be surrounded by enthusiastic people with helpful ideas.