The functions of the frontal lobes: Evidence from patients with focal brain damage.

Patients with focal frontal lobe damage have long been a crucial source of information about the role of this region in human behavior. This method remains the only means to provide inferentially powerful loss-of-function evidence for many regions within the human frontal lobes. This chapter demonstrates modern focal lesion research methods, focusing on specific subregions within prefrontal cortex, and their contributions to widely studied aspects of executive function and decision-making. Examples of such studies are reviewed in detail, to demonstrate the strengths, limitations, and logic of lesion methods. The evidence provided by such studies is considered in relation to converging evidence from other cognitive neuroscience methods. The tensions between modular and network views of prefrontal function are also addressed. Lesion studies straddle fundamental and clinical neuroscience, allowing basic advances in this area to be readily translated to psychiatric and neurologic disorders. This unique position, as well as the ability to test causal claims, explains the staying power of this classic approach to understanding the brain basis of behavior.