Type of Study: Research Study

Subjects: Patients with focal frontal lobe lesions

Purpose: The examination of patients with focal frontal lobe lesions is a necessary first step in defining the relation of executive functions to the frontal lobes:

•The purpose of their study was to determine whether unitary executive function exists
•A simple control-automatic distinction is adequate to explain the complexity of control-automatic processes
•The distinction between complex and simple tasks can explain differences in functions between the frontal lobes and other brain regions
•The most important role of the frontal lobes may be for affective responsiveness, social and personality development, and self-awareness and unconsciousness.

Methods: Three different groups of patients with focal frontal lobe lesions were compared on a word-list learning task. These patients performed fluency tasks.

Results:

•That different anterior attentional processes can be isolated
•Simple processes can be related to the frontal lobes
•There is an interaction between anterior and posterior attentional processes, suggesting that the only way to discuss the results is to use the concepts of neural functional systems
•Task demands alter the interaction of neural systems
•Inhibition is not simply a function of the frontal lobes.

Discussion: The data from this study support the proposition that distinct processes are related to different regions of the frontal lobes. For the processes that underlie self-awareness, current evidence from both lesion studies and activation studies points to a critical role for the right frontal lobe.