More than any other subspecialty area of neurology, behavioral neurology addresses those brain functions that uniquely define us as humans. Often these capacities are not easily explicable by simple neuroanatomic pathways, but rather involve complex neural networks. In this issue of Continuum, Dr Murray Grossman has recruited some of the most renowned experts in the field, as well as some rising stars, to offer not only clear explanations where they are known but current plausible theoretical discussion where information is less firmly established. I have no doubt that you will find this issue fascinating and enlightening.
Disorders of memory are perhaps the most frequent behavioral disturbances encountered in neurologic practice. When severe, such impairment is among the most incapacitating neurologic conditions. But not all memory is the same. In the first article of this issue, Drs David Wolk and Andrew Budson review amnestic impairments in the context of discussions of episodic, semantic, and procedural memory.
The next three articles are devoted to aspects of symbolic language function, a capacity that is perhaps an absolutely unique aspect of the human condition. In this context extensive neural networks are implicated and the impact of so-called disconnection syndromes is recognized. First, Dr Argye Hillis discusses the expressive elements of language in her article, "Naming and Language Production." Drs HyungSub Shim and Thomas Grabowski follow this with an analysis of the receptive components of language. Of course, speech is not the only form of communication; written language is also of major importance. While disorders of reading and writing frequently follow, pari passu, with those of spoken language, some times impairments in dealing with written language occur independently. Drs David Roeltgen and Elizabeth Lacey analyze alexias and agraphias in their article, "Reading, Writing, and Their Disorders."
Communication between people is not confined to language. We not only express emotions but need to recognize emotion and social signals from others. Although this has been a much less well-studied area of human behavior than language, the concepts and the nature of the investigations are fascinating. Drs Marc Sollberger, Katherine Rankin, and Bruce Miller bring you up to speed on the current status of this aspect of human behavior in their article on social cognition.
As a student and resident in neurology, I was particularly intrigued by the notion of apraxia, the inability to perform skilled motor acts despite the preservation of the sensorimotor apparatus to do so. I suspect that you are similarly fascinated. Dr Kenneth Heilman, who has been one of the most thoughtful and productive investigators on this subject, illuminates the various forms of apraxia.
Vision is, of course, one of the most critical tools with which humans acquire information about their environment. How the brain processes information gained through this special sense is the subject of discussion in the next two articles of this issue. Drs Anjan Chatterjee and H. Branch Coslett first address disorders of visuospatial processing, including discussion of the fairly common phenomenon of neglect, as well as elements that comprise Balint syndrome and visuospatial deficits that accompany dementia. Then Dr Jason Barton focuses specifically on disorders of color and object recognition, which include the important subject of facial processing and its disorder, prosopagnosia.
In order to set the stage for the full panoply of human behavior, individuals must be in a state of alertness and able to attend properly to a variety of stimuli. Disturbances of attention, as well as confusional states, are among the most frequent reasons for neurologic consultation in the hospital setting. Dr M.-Marsel Mesulam, a foremost authority on the subject, presents the current state of knowledge in his article, "Attentional and Confusional States."
The ability to plan, organize, and carry out complex tasks is another critical aspect of human behavior, known as executive function. A variety of disorders impair this neurobehavioral capacity, particularly degenerative disorders including perhaps most notably frontotemporal dementia. Dr Rachel Gross, and Guest Editor Grossman discuss this important subject in their article, "Executive Resources."
In the Ethical Perspectives in Neurology section of this issue, Dr Daniel Larriviere addresses the "stimulating" question of prescriptions for neuroenhancement. Dr Stephen Nadeau follows this with his practical advice on optimizing cognitive function in the cognitively fragile patient in the section Practice Issues in Neurology.
As usual, I exhort you to maximize your educational experience of this issue of \raster(15%,p)="rg7" by working through the Patient Management Problem contributed by Dr William Hu, as well as the Multiple-Choice Questions prepared by Drs Eduardo Benarroch and Joanne Lynn. Remember that you can easily achieve CME credits by submitting the answers to the questions online.
I am confident that you will share my enthusiasm about the exhilarating trip through the spectrum of human behavior provided by this issue. We are grateful to Dr Grossman and his outstanding faculty for serving as our guides.
-Aaron E. Miller, MD