ABSTRACT
For more than a century, the lesion-behavior method has grounded the development of insights in the functional anatomy of the brain and the neural organization of cognitive functions. The attempt to establish a direct relation between injury in a specific brain region and cognitive manifestations dates back to Jean-Baptiste Bouillaud (1825), who linked disruption of oral language functions in a series of aphasic patients to postmortem findings of frontal lobe damage. The modern era of anatomoclinical insights in neuropsychological and neurobehavioral syndromes started in the 1860s in Paris with Paul Broca’s seminal contributions to the Société d’Anthropologie. In the course of 4 years of intensive discussions about the representation of language functions in the brain, Broca presented clinical and neuroanatomical evidence that established a correlation between expressive aphasia and damage to the frontal region of the language-dominant hemisphere (that is, the left hemisphere in dextrals and the right hemisphere in sinistrals). New concepts and methods of investigation exposed during the debates on the localization of speech rapidly extended to other aspects of language and related cognitive areas. During the last decades of the nineteenth century, vigorous application of the lesion-behavior method led to several innovative insights and influential discoveries in the understanding of brain-behavior relationships. In 1874, the German neurologist Carl Wernicke introduced the prototype of fluent aphasia that substantially differed from Broca’s nonfluent, expressive variant following frontal lobe damage. In his monograph Der aphasische Symptomencomplex, Wernicke (1874) described what he called “sensory aphasia” following structural damage to the posterior part of the superior temporal gyrus of the language-dominant hemisphere. In addition, Wernicke identified global aphasia and conduction aphasia on the basis of a model that explained aphasic syndromes as the result of lesions affecting different, noncontiguous language centers and their unidirectional anatomical connections capable of performing a variety of complex functions with relative independence. During
the last decades of the nineteenth century, a considerable expansion of knowledge about specific aspects of aphasia and related disorders was realized. Déjerine (1892), for instance, elucidated the neuranatomic substrate of pure alexia, Brissaud (1894) described the phenomenon of prosodic speech disturbances (aphasie d’intonation), and Pitres called attention to aphasia in polyglots (Pitres, 1895) and to the syndrome of amnestic aphasia (Pitres, 1898). In this period of intense experimental, clinical, and anatomoclinical activity, a variety of neuropsychological functions and skills were localized as well. Munk (1878) first identified “cortical blindness” and “mindblindedness” as examples of higher-level impairment of visual perception and recognition after occipital lobe lesions. Freud (1891) coined the term “agnosia” to denote the phenomenon of disrupted recognition skills. Astereognosis as the somesthetic counterpart of visual agnosia was described by Hoffmann (1885) and related to damage of the postcentral gyrus by Wernicke (1895). Diverse forms of apraxia after focal lesions of the language-dominant hemisphere were described during the first decades of the twentieth century (Liepmann, 1900; Strauss, 1924). By contrast, the early scattered attempts to demonstrate that the nondominant right hemisphere also possesses some distinctive functional qualities in the regulation of cognitive behavior had no significant influence on the development of neuropsychological knowledge until after World War II.
