The Brain and the World: Unuttered Language

In 2007, Professor Paul de Saint-Maur was travelling through Paris with a peculiar piece of cargo. From its usual resting place at Musee Dupuytren to the Neuroradiology Department at Hôpital des Quinze-Vingts, the professor brought with him a brain. Probably the most important brain of the 19th century. Not the brain of Napoleon or Marx or Darwin, this brain had once rested in the skull of an epileptic craftsman. His name was Louis Victor Leborgne, but the scientific community of 1861 had come to know him as “Tan”.

In the first half of the 19th century, the paradigm of cerebral localization was heavily debated. The idea that specific areas of the brain served specific functions had been introduced by phrenologist Franz Joseph Gall, but because phrenology was an obvious sham, serious scientists struggled to reintroduce cerebral localization as a credible concept. The conservative view was that the mind was indivisible, and that the brain as a whole performed the faculties of perception, memory and intellect. The Tan case would shift the paradigm in favor of localization.

Louis Victor Leborgne had lost the ability to speak at the age of 21, probably due to epileptic seizures. He was hospitalized at Bicêtre Hospital in 1840 and would stay there for the remaining twenty-one years of his life. Though able to understand words spoken by others, he could utter only the one syllable “tan”, earning him that nickname throughout the hospital. In 1861, now a dying man, Leborgne was transferred to the department of physician Paul Broca.

At this point in his life, Broca was a highly respected physician, anatomist and anthropologist. He had been the vice president of Society Anatomique de Paris, he had founded the Société d’Anthropologie de Paris, and he had contributed extensively to the scientific community. Broca saw the speech impediment as an easily accessible test case for localization of language. In Broca’s own description of Tan, “[he] could no longer produce but a single syllable, which he usually repeated twice in succession; regardless of the question asked him, he always responded: tan, tan, combined with varied expressive gestures.”

When Tan died six days later, Broca performed the autopsy and identified a lesion in the left frontal lobe.

A few months later, Broca encountered another patient with a similar disorder. After suffering from a stroke, Lazare Lelong could utter five words; “oui” and “non” meaning yes and no, “toujours” meaning always, “Lelo” as a mispronunciation of his own name, and “tois” as a mispronunciation of “trois” meaning three and which he would substitute for any number. At autopsy, Broca found a lesion approximately in the same region as the first case, leading him to the conclusion that the left frontal lobe was indispensable to the ability to articulate language.

Broca presented the findings to the Société d’Anthropologie and to the Society Anatomique de Paris. The timing was right, and the respect for Paul Broca in the scientific community certainly aided the support for his conclusions. In the following years, Broca was presented with similar cases of aphasia and found in most of the cases a lesion at the same location in the left frontal lobe. This part of the brain is now termed Broca’s Area in a tribute to the man who not only localized language, but shifted the paradigm of neurology.

In the following decades, specific cognitive functions were localized to specific areas of the brain; Vision and the interpretation of sight was localized to the posterior parts of the brain, memory and the ability to learn was localized to the deep hippocampal structure, motor functions of the right part of the body was localized to the left hemisphere and vice versa.

High-resolution MRI of the preserved brain of
Leborgne. In Dronkers et al, 2007.

For more than a century, neurologists excelled in the art of localizing cerebral lesions based on clinical findings. It would take a new technological tool to support and extend these understandings. The tool was imaging, and this was what prompted Professor Saint-Maur to carry the brain of Leborgne through Paris. Broca had preserved the brains in alcohol, allowing posterity to examine them. His intention was fulfilled in 2007 when MRI scans were performed. The images revealed lesions extending deeper into the brains than originally reported, demonstrating areas of language function that had been inaccessible to Broca. The neuroscientists at the Neuroradiology Department at Hôpital des Quinze-Vingts acknowledged that Leborgne and Lelong “speak to us more eloquently now than they could over 140 years ago.”

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Dronkers NF, Plaisant O, Iba-Zizen MT, Cabanis EA. Paul Broca's historic cases: high resolution MR imaging of the brains of Leborgne and Lelong. Brain. 2007.

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Find all chapters of

The History of the Brain

here:

I: Violent beginnings

II: Pulp Appendix

III: Disappointing Anatomy

IV: Map of Darkness

V: Unuttered Language

VI: Ode to Cajal

VII: Picture This

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