Neurolinguistics - History

History

Further information: History of the brain, History of neuroscience, History of neuroimaging, and History of cognitive science

Neurolinguistics is historically rooted in the development in the 19th century of aphasiology, the study of linguistic deficits (aphasias) occurring as the result of brain damage. Aphasiology attempts to correlate structure to function by analyzing the effect of brain injuries on language processing. One of the first people to draw a connection between a particular brain area and language processing was Paul Broca, a French surgeon who conducted autopsies on numerous individuals who had speaking deficiencies, and found that most of them had brain damage (or lesions) on the left frontal lobe, in an area now known as Broca's area. Phrenologists had made the claim in the early 19th century that different brain regions carried out different functions and that language was mostly controlled by the frontal regions of the brain, but Broca's research was possibly the first to offer empirical evidence for such a relationship, and has been described as "epoch-making" and "pivotal" to the fields of neurolinguistics and cognitive science. Later, Carl Wernicke, after whom Wernicke's area is named, proposed that different areas of the brain were specialized for different linguistic tasks, with Broca's area handling the motor production of speech, and Wernicke's area handling auditory speech comprehension. The work of Broca and Wernicke established the field of aphasiology and the idea that language can be studied through examining physical characteristics of the brain. Early work in aphasiology also benefited from the early twentieth-century work of Korbinian Brodmann, who "mapped" the surface of the brain, dividing it up into numbered areas based on each area's cytoarchitecture (cell structure) and function; these areas, known as Brodmann areas, are still widely used in neuroscience today.

The coining of the term "neurolinguistics" has been attributed to Harry Whitaker, who founded the Journal of Neurolinguistics in 1985.

Although aphasiology is the historical core of neurolinguistics, in recent years the field has broadened considerably, thanks in part to the emergence of new brain imaging technologies (such as PET and fMRI) and time-sensitive electrophysiological techniques (EEG and MEG), which can highlight patterns of brain activation as people engage in various language tasks; electrophysiological techniques, in particular, emerged as a viable method for the study of language in 1980 with the discovery of the N400, a brain response shown to be sensitive to semantic issues in language comprehension. The N400 was the first language-relevant brain response to be identified, and since its discovery EEG and MEG have become increasingly widely used for conducting language research.