Book Review

The Human Frontal Lobes: Functions and Disorders

N Engl J Med 2007; 356:2332-2333May 31, 2007

Article

The Human Frontal Lobes: Functions and Disorders
(The Science and Practice of Neuropsychology.) Second edition. Edited by Bruce L. Miller and Jeffrey L. Cummings. 666 pp., illustrated. New York, Guilford Press, 2007. $95. ISBN: 978-1-59385-329-7

The evolution of the human frontal lobes lies at the very essence of the characteristic behavior of humans. Everyday traits that define our existence, both socially and as individuals, have important substrates in the frontal lobes: humor, intuition and insight, deception and truthfulness, optimism and skepticism, affection and hatred, and inspiration. One of the great tragedies for patients and their families is a disease of the frontal lobes that destroys the distinctive personality around which a whole life has been built.

In this book, Bruce Miller and Jeffrey Cummings have done a fine job in drawing together the disparate strands of current scientific knowledge that are allowing us to begin to understand this most integrative part of the brain and its particular concern with abstract subject matters. A distinguished team of authors discuss anatomy, neurochemistry, neuropathology, and psychiatric disease. They take us from the functional anatomical subdivisions to the neurobiology. We learn that the medial frontal area is involved with motivation, the orbitofrontal area with rules of social convention, and the dorsolateral prefrontal area with the planning of actions. Tau proteins are required for microtubule stability within neurons and are affected by a rapidly emerging myriad of genetic and acquired abnormalities that underlie the particularly distressing syndrome of frontotemporal dementia.

Any contemporary study of the frontal lobes faces particular challenges in understanding their evolution, in devising neuropsychological tests that reflect everyday concepts of the mind, and in using functional imaging to localize neuropsychological processes and to explore their interdependencies. The role of a cell distinctive to the frontal cortex, the spindle neuron, is fascinating. A few are present in great apes, but they are truly abundant in humans. Do they harbor some singular processing power that is key to the integrative and abstract functioning of the frontal lobes?

Neuropsychological testing paradigms often carry an uncertain or tenuous relationship to what we recognize as everyday thoughts, behaviors, and actions. Although this topic is potentially one of the less penetrable areas of such a book, the authors do a decent job of illuminating the role the frontal lobes play in autobiographical memory, executive control, planning, and episodic memory by referencing such tests. It is a pity this book does not explore the emerging use of functional magnetic resonance imaging to dissect processes such as deception or interpretation of one's body state. The frontal lobes seem to be the substrate for these ubiquitous aspects of human behavior, which many try to ignore but which are familiar to all doctors in the clinical settings of malingering, hysteria, and somatization.

The last section of the book is devoted to how the frontal lobes may be involved in the genesis of important disorders such as schizophrenia, bipolar disorder, obsessive–compulsive disorder, and autism. This is a crucial area of study, because the manifestations of these disorders so obviously involve abnormalities in functions for which the frontal lobes are uniquely responsible: motivation, rational thought, and socialization. This section illustrates the great difficulty of following the traditional medicopathologic holy grail of trying to discern whether there is a single, definable cause for such diseases. Or is there a more nebulous concept of distortion and imbalance at work in the frontal-brain circuits responsible for thoughts, impulses, and behavior? Given the emerging understanding of the role of genetics in autism, functional imaging of the various entities of autism may help to illuminate frontal-lobe function. Although it is not stated overtly, this section of the book raises optimism that a new era of imaging, one that addresses the functional circuitry of the frontal lobes, may hold the key to pharmaceutical interventions in several important disorders, even if their particular causes remain elusive for some time to come. We need to acknowledge — in much the same way we are beginning to understand the genesis of migraine — that some disorders may be caused by problems within the brain's functional circuitry rather than by damage to individual components.

With the very substrate of human nature as its theme, this book brings together hugely disparate disciplines concerning the role of the frontal lobes in health and disease. Although its accessibility and general interest might have been enhanced by more overview and speculation, it is heartily recommended to anyone interested in this daunting and emerging area of neuroscience.

Michael Donaghy, D.Phil., F.R.C.P.
University of Oxford, Oxford OX3 9DU, United Kingdom