Re-examining Paul Broca's initial presentation of M. Leborgne: Understanding the impetus for brain and language research
ABSTRACT The 150th anniversary affords an opportunity to revisit the circumstances surrounding Paul Broca's case report celebrated today as the moment of discovery of aphasia. The proceedings from January to June 1861 of the Paris Society of Anthropology are examined to reconstruct the events surrounding the report of M. Leborgne on April 18th. From a close reading of the presentations and discussions which took place during this period it is apparent that Broca's case report was a minor diversion to a debate about cranial measurements and their relation to intelligence in individuals and racial groups. Moreover, it appears that little attention was granted to Broca's first case at the time. While his ideas about localization and specialization developed and change over the next decade, it represented a minor field of interest for him. Nevertheless Broca's work on aphasia inspired research throughout Europe and North America and went on to have a lasting impact on both aphasiology and neuropsychology.
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ABSTRACT: Last year was the 150th anniversary of Paul Broca's landmark case report on speech disorder that paved the way for subsequent studies of cortical localization of higher cognitive functions. However, many complex functions rely on the activity of distributed networks rather than single cortical areas. Hence, it is important to understand how brain regions are linked within large-scale networks and to map lesions onto connecting white matter tracts. To facilitate this network approach we provide a synopsis of classical neurological syndromes associated with frontal, parietal, occipital, temporal and limbic lesions. A review of tractography studies in a variety of neuropsychiatric disorders is also included. The synopsis is accompanied by a new atlas of the human white matter connections based on diffusion tensor tractography freely downloadable on http://www.natbrainlab.com. Clinicians can use the maps to accurately identify the tract affected by lesions visible on conventional CT or MRI. The atlas will also assist researchers to interpret their group analysis results. We hope that the synopsis and the atlas by allowing a precise localization of white matter lesions and associated symptoms will facilitate future work on the functional correlates of human neural networks as derived from the study of clinical populations. Our goal is to stimulate clinicians to develop a critical approach to clinico-anatomical correlative studies and broaden their view of clinical anatomy beyond the cortical surface in order to encompass the dysfunction related to connecting pathways.Cortex 08/2012; 48(10):1262-87. DOI:10.1016/j.cortex.2012.07.001 · 6.04 Impact Factor
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ABSTRACT: As of spring 2011, 150 years have passed since the death of one of the most famous neurological patients of the nineteenth century. A Frenchman, "Monsieur Leborgne" also known by the nickname "Tan," was hospitalized due to an almost complete loss of speech. His case was presented in 1861, during a seating of the Société d'Anthropologie de Paris by a physician, Pierre Paul Broca (1824-1880), who used this occasion to report that he had discovered, in the middle part of patient's left frontal lobe, the cortical speech center. This area was later named "Broca's area." Both the patient and his medical records were the subject of numerous descriptions and citations in the medical literature. The patient's full identity and social background has remained a mystery until now. This article presents biographical data concerning Leborgne and his family based on archive registers in France.Journal of the history of the neurosciences 01/2013; 22(1):47-52. DOI:10.1080/0964704X.2012.667528 · 0.54 Impact Factor
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ABSTRACT: Apolipoprotein E (apoE) is involved in lipid metabolism in the brain, but its effects on brain function are not understood. Three apoE isoforms (E4, E3, and E2) are the result of cysteine-arginine interchanges at two sites: there are zero interchanges in E4, one interchange in E3, and two interchanges in E2. The resulting six apoE genotypes (E4/4, E4/3, E4/2, E3/3, E3/2, E2/2) yield five groups with respect to the number of cysteine residues per mole (CysR/mole), as follows. ApoE4/4 has zero cysteine residues per mole (0-CysR/mole), E4/3 has one (1-CysR/mole), E4/2 and E3/3 each has two (2-CysR/mole), E3/2 has three (3-CysR/mole), and E2/2 has four (4-CysR/mole). The use of the number of CysR/mole to characterize the apoE molecule converts the categorical apoE genotype scale, consisting of 6 distinct genotypes above, to a 5-point continuous scale (0-4 CysR/mole). This allows the use of statistical analyses suitable for continuous variables (e.g. regression) to quantify the relations between various variables and apoE. Using such analyses, here, we show for the first time that apoE affects in a graded and orderly manner neural communication, as assessed by analyzing the relation between the number of CysR/mole and synchronous neural interactions (SNI) measured by magnetoencephalography (MEG) in 130 cognitively healthy women. At the one end of the CysR/mole range, the 4-CysR/mole (E2/2) SNI distribution had the highest mean, lowest variance, lowest range, and lowest coefficient of variation, whereas at the other end, 0-CysR/mole (E4/4) SNI distribution had the lowest mean, highest variance, highest range, and highest coefficient of variation. The special status of the 4-CysR/mole distribution was reinforced by the results of a hierarchical tree analysis where the 4-CysR/mole (E2/2) SNI distribution occupied a separate branch by itself and the remaining CysR/mole SNI distributions were placed at increasing distances from the 4-CysR/mole distribution, according to their number of CysR/mole, with the 0-CysR/mole (E4/4) being farthest away. These findings suggest that the 4-CysR/mole (E2/2) SNI distribution could serve as a reference distribution. When the SNI distributions of individual women were expressed as distances from this reference distribution, there was a substantial overlap among women of various CysR/mole. This refocuses the placement of individual brains along a continuous distance from the 4-CysR/mole SNI distribution, in contrast to the common categorical assignment to a specific apoE genotype. Finally, the orderly variation of SNI with the number of CysR/mole found here is in keeping with recent advances and ideas regarding the molecular mechanisms underlying the differential effects of apoE in the brain which emphasize the healthier stability conferred on the apoE molecule by the increasing number of cysteine-arginine interchanges, with 4-CysR/mole (E2/2) being the best case, as opposed to the instability and increased chance of toxic fragmentation of the apoE molecule with lower number of CysR/mole, with 0-CysR/mole (E4/4) as the worst case (Mahley and Huang in Neuron 76:871-885, 2012a). However, our results also document the appreciable variation of SNI properties within the various CysR/mole groups and individuals which points to the existence and important role of other factors involved in shaping brain function at the network level.Experimental Brain Research 03/2013; 226(4). DOI:10.1007/s00221-013-3464-x · 2.17 Impact Factor