A Parisian spring: the debate on language localization at the Imperial Academy of Medicine, Paris, April 4-June 13, 1865.

The localization of articulate language (speech) to the posterior third of the third left frontal convolution-Broca's area-did not occur to Broca as he reported the case of his first aphasic patient in 1861. Initially Broca localized articulate language to both frontal lobes, a position that he maintained for 4 years after publishing his first case. In the interval, the Academy of Medicine in Paris had received a copy of a paper authored in 1836 by Marc Dax, in which Dax claimed that the ability to speak resides within the left hemisphere alone. The Academy of Medicine convened in the spring of 1865 to adjudicate the issue. All of the distinguished speakers argued against Dax's contention by citing the prevailing paradigm, that bilaterally symmetrical organs, such as the eyes and ears, and the hemispheres of the brain, must perform the same function. The lone dissenting voice was that of Jules Baillarger, the discoverer of the laminar organization of the cerebral cortex, whose argument in favor of what he called "Dax's law" was so lucid that it carried the day. During his address to the Academy, Baillarger not only supported left-hemisphere dominance for speech, but for the first time described two forms of aphasia, fluent and nonfluent, now referred to as Wernicke's and Broca's aphasias, respectively, as well as the ability of aphasics to speak during emotional outbursts, to which we now refer as Baillarger-Jackson aphasia. It was 9 days after Baillarger's address that Broca, for the first time, unequivocally localized speech to the left frontal lobe.This paper is based on the author's reading of Dax's and Broca's original texts and of the texts read before the Academy of Medicine meeting held at the National Library of France between April 4, 1865, and June 13, 1865. From these primary sources it is concluded that the Academy of Medicine's debate was the last serious challenge to left-hemisphere dominance for speech and to the localization of articulate language to the left frontal lobe-and that Jules Baillarger played a pivotal role in what was a defining moment in neurobiology.

Mapping language dominance through the lens of the Wada test.

The sodium amytal test, or Wada test, named after Juhn Wada, has remained a pillar of presurgical planning and is used to identify the laterality of the dominant language and memory areas in the brain. What is perhaps less well known is that the original intent of the test was to abort seizure activity from an affected hemisphere and also to protect that hemisphere from the effects of electroconvulsive treatment. Some 80 years after Paul Broca described the frontal operculum as an essential area of expressive language and well before the age of MRI, Wada used the test to determine language dominance. The test was later adopted to study hemispheric memory dominance but was met with less consistent success because of the vascular anatomy of the mesial temporal structures. With the advent of functional MRI, the use of the Wada test has narrowed to application in select patients. The concept of selectively inhibiting part of the brain to determine its function, however, remains crucial to understanding brain function. In this review, the authors discuss the rise and fall of the Wada test, an important historical example of the innovation of clinicians in neuroscience.

Cross-cultural consistency and diversity in intrinsic functional organization of Broca's Region.

As a core language area, Broca's region was consistently activated in a variety of language studies even across different language systems. Moreover, a high degree of structural and functional heterogeneity in Broca's region has been reported in many studies. This raised the issue of how the intrinsic organization of Broca's region effects by different language experiences in light of its subdivisions. To address this question, we used multi-center resting-state fMRI data to explore the cross-cultural consistency and diversity of Broca's region in terms of its subdivisions, connectivity patterns and modularity organization in Chinese and German speakers. A consistent topological organization of the 13 subdivisions within the extended Broca's region was revealed on the basis of a new in-vivo parcellation map, which corresponded well to the previously reported receptorarchitectonic map. Based on this parcellation map, consistent functional connectivity patterns and modularity organization of these subdivisions were found. Some cultural difference in the functional connectivity patterns was also found, for instance stronger connectivity in Chinese subjects between area 6v2 and the motor hand area, as well as higher correlations between area 45p and middle frontal gyrus. Our study suggests that a generally invariant organization of Broca's region, together with certain regulations of different language experiences on functional connectivity, might exists to support language processing in human brain.

Convergence of semantics and emotional expression within the IFG pars orbitalis.

Humans communicate through a combination of linguistic and emotional channels, including propositional speech, writing, sign language, music, but also prosodic, facial, and gestural expression. These channels can be interpreted separately or they can be integrated to multimodally convey complex meanings. Neural models of the perception of semantics and emotion include nodes for both functions in the inferior frontal gyrus pars orbitalis (IFGorb). However, it is not known whether this convergence involves a common functional zone or instead specialized subregions that process semantics and emotion separately. To address this, we performed Kernel Density Estimation meta-analyses of published neuroimaging studies of the perception of semantics or emotion that reported activation in the IFGorb. The results demonstrated that the IFGorb contains two zones with distinct functional profiles. A lateral zone, situated immediately ventral to Broca's area, was implicated in both semantics and emotion. Another zone, deep within the ventral frontal operculum, was engaged almost exclusively by studies of emotion. Follow-up analysis using Meta-Analytic Connectivity Modeling demonstrated that both zones were frequently co-activated with a common network of sensory, motor, and limbic structures, although the lateral zone had a greater association with prefrontal cortical areas involved in executive function. The status of the lateral IFGorb as a point of convergence between the networks for processing semantic and emotional content across modalities of communication is intriguing since this structure is preserved across primates with limited semantic abilities. Hence, the IFGorb may have initially evolved to support the comprehension of emotional signals, being later co-opted to support semantic communication in humans by forming new connections with brain regions that formed the human semantic network.

Sexual dimorphism of Broca's region: More gray matter in female brains in Brodmann areas 44 and 45.

Although a sexual dimorphism in brain structure is generally well established, evidence for sex differences in Brodmann areas (BA) 44 and 45 is inconclusive. This may be due to the difficulty of accurately defining BA 44 and BA 45 in magnetic resonance images, given that these regions are variable in their location and extent and that they do not match well with macroanatomic landmarks. Here we set out to test for possible sex differences in the local gray matter of BA 44/45 by integrating imaging-based signal intensities with cytoarchitectonically defined tissue probabilities in a sample of 50 male and 50 female subjects. In addition to testing for sex differences with respect to left- and right-hemispheric measures of BA 44/45, we also assessed possible sex differences in BA 44/45 asymmetry. Our analyses revealed significantly larger gray matter volumes in females compared with males for BA 44 and BA 45 bilaterally. However, there was a lack of significant sex differences in BA 44/45 asymmetry. These results corroborate reports of a language-related female superiority, particularly with respect to verbal fluency and verbal memory tasks. © 2016 Wiley Periodicals, Inc.

Investigation of topographical anatomy of Broca's area: an anatomic cadaveric study.

PURPOSE: The sulci constituting the structure of the pars triangularis and opercularis, considered as 'Broca's area', present wide anatomical and morphological variations between different hemispheres. The boundaries are described differently from one another in various studies. The aim of this study was to explore the topographical anatomy, confirm the morphological asymmetry and highlight anatomical variations in Broca's area. METHODS: This study was performed with 100 hemispheres to investigate the presence, continuity, patterns and connections of the sulcal structures that constitute the morphological asymmetry of Broca's area. RESULTS: Considerable individual anatomical and morphological variations between the inferior frontal gyrus and related sulcal structures were detected. Rare bilateralism findings supported the morphological asymmetry. The inferior frontal sulcus was identified as a single segment in 54 % of the right and two separate segments in 52 % of the left hemispheres, which was the most common pattern. The diagonal sulcus was present in 48 % of the right and 54 % of the left hemispheres. It was most frequently connected to the ascending ramus on both sides. A 'V' shape was observed in 42.5 % of the right hemispheres and a 'Y' shape in 38.3 % of the left hemispheres, which was the most common shape of the pars triangularis. Moreover, the full results are specified in detail. CONCLUSIONS: Knowledge of the anatomical variations in this region is indispensable for understanding the functional structure and performing safe surgery. However, most previously published studies have aimed to determine the anatomical asymmetry of the motor speech area without illuminating the topographical anatomy encountered during surgery.

How the brain learns how few are "many": An fMRI study of the flexibility of quantifier semantics.

Previous work has shown that the meaning of a quantifier such as "many" or "few" depends in part on quantity. However, the meaning of a quantifier may vary depending on the context, e.g. in the case of common entities such as "many ants" (perhaps several thousands) compared to endangered species such as "many pandas" (perhaps a dozen). In a recent study (Heim et al., 2015 Front. Psychol.) we demonstrated that the relative meaning of "many" and "few" may be changed experimentally. In a truth value judgment task, displays with 40% of circles in a named color initially had a low probability of being labeled "many". After a training phase, the likelihood of acceptance 40% as "many" increased. Moreover, the semantic learning effect also generalized to the related quantifier "few" which had not been mentioned in the training phase. Thus, fewer 40% arrays were considered "few." In the present study, we tested the hypothesis that this semantic adaptation effect was supported by cytoarchitectonic Brodmann area (BA) 45 in Broca's region which may contribute to semantic evaluation in the context of language and quantification. In an event-related fMRI study, 17 healthy volunteers performed the same paradigm as in the previous behavioral study. We found a relative signal increase when comparing the critical, trained proportion to untrained proportions. This specific effect was found in left BA 45 for the trained quantifier "many", and in left BA 44 for both quantifiers, reflecting the semantic adjustment for the untrained but related quantifier "few." These findings demonstrate the neural basis for processing the flexible meaning of a quantifier, and illustrate the neuroanatomical structures that contribute to variable meanings that can be associated with a word when used in different contexts.

Subdivision of Broca's region based on individual-level functional connectivity.

Broca's region is composed of two adjacent cytoarchitectonic areas, 44 and 45, which have distinct connectivity to superior temporal and inferior parietal regions in both macaque monkeys and humans. The current study aimed to make use of prior knowledge of sulcal anatomy and resting-state functional connectivity, together with a novel visualization technique, to manually parcellate areas 44 and 45 in individual brains in vivo. One hundred and one resting-state functional magnetic resonance imaging datasets from the Human Connectome Project were used. Left-hemisphere surface-based correlation matrices were computed and visualized in brainGL. By observation of differences in the connectivity patterns of neighbouring nodes, areas 44 and 45 were manually parcellated in individual brains, and then compared at the group-level. Additionally, the manual labelling approach was compared with parcellation results based on several data-driven clustering techniques. Areas 44 and 45 could be clearly distinguished from each other in all individuals, and the manual segmentation method showed high test-retest reliability. Group-level probability maps of areas 44 and 45 showed spatial consistency across individuals, and corresponded well to cytoarchitectonic probability maps. Group-level connectivity maps were consistent with previous studies showing distinct connectivity patterns of areas 44 and 45. Data-driven parcellation techniques produced clusters with varying degrees of spatial overlap with the manual labels, indicating the need for further investigation and validation of machine learning cortical segmentation approaches. The current study provides a reliable method for individual-level cortical parcellation that could be applied to regions distinguishable by even the most subtle differences in patterns of functional connectivity.

Variations in size, shape and asymmetries of the third frontal convolution in hominids: paleoneurological implications for hominin evolution and the origin of language.

The study of brain structural asymmetries as anatomical substrates of functional asymmetries in extant humans, great apes, and fossil hominins is of major importance in understanding the structural basis of modern human cognition. We propose methods to quantify the variation in size, shape and bilateral asymmetries of the third frontal convolution (or posterior inferior frontal gyrus) among recent modern humans, bonobos and chimpanzees, and fossil hominins using actual and virtual endocasts. These methodological improvements are necessary to extend previous qualitative studies of these features. We demonstrate both an absolute and relative bilateral increase in the size of the third frontal convolution in width and length between Pan species, as well as in hominins. We also observed a global bilateral increase in the size of the third frontal convolution across all species during hominin evolution, but also non-allometric intra-group variations independent of brain size within the fossil samples. Finally, our results show that the commonly accepted leftward asymmetry of Broca's cap is biased by qualitative observation of individual specimens. The trend during hominin evolution seems to be a reduction in size on the left compared with the right side, and also a clearer definition of the area. The third frontal convolution considered as a whole projects more laterally and antero-posteriorly in the right hemisphere. As a result, the left 'Broca's cap' looks more globular and better defined. Our results also suggest that the pattern of brain asymmetries is similar between Pan paniscus and hominins, leaving the gradient of the degree of asymmetry as the only relevant structural parameter. As the anatomical substrate related to brain asymmetry has been present since the appearance of the hominin lineage, it is not possible to prove a direct relationship between the extent of variations in the size, shape, and asymmetries of the third frontal convolution and the origin of language in hominins.

Cortical thickness of Broca's area and right homologue is related to grammar learning aptitude and pitch discrimination proficiency.

Aptitude for and proficiency in acquiring new languages varies in the human population but their neural bases are largely unknown. We investigated the influence of cortical thickness on language learning predictors measured by the LLAMA tests and a pitch-change discrimination test. The LLAMA tests are first language-independent assessments of language learning aptitude for vocabulary, phonetic working memory, sound-symbol correspondence (not used in this study), and grammatical inferencing. Pitch perception proficiency is known to predict aptitude for learning new phonology. Results show a correlation between scores in a grammatical meaning-inferencing aptitude test and cortical thickness of Broca's area (r(30) = 0.65, p = 0.0202) and other frontal areas (r(30) = 0.66, p = 0.0137). Further, a correlation was found between proficiency in discriminating pitch-change direction and cortical thickness of the right Broca homologue (r(30) = 0.57, p = 0.0006). However, no correlations were found for aptitude for vocabulary learning or phonetic working memory. Results contribute to locating cortical regions important for language-learning aptitude.

The robust and independent nature of structural STS asymmetries.

The superior temporal sulcus (STS) is an important region for speech comprehension. The greater language network is known to exhibit asymmetries in both structure and function, and consistent with that theory are reports of STS structural asymmetry in MRI-based, morphological measures such as mean thickness and sulcal depth. However, it is not known how these individual STS structural asymmetries relate to each other, or how they interact with the broader language asymmetry that manifests in other brain regions. In this study, we assess the interrelations of STS asymmetries in the human brain in vivo, using four independent datasets to validate our findings. For morphological measurements, we identify STS laterality effects consistent between our datasets and with the literature: leftward for surface area, and rightward for sulcal depth and mean thickness. We then add two more measurements of STS asymmetry: in T1, a quantitative index of the tissue's underlying biophysical properties; and in the projections to the STS from the arcuate fasciculus, a left-lateralized white-matter bundle that connects temporal regions (including STS) with frontal regions (including Broca's area). For these two new measurements, we identify no effect for T1 and a leftward effect for arcuate projections. We then test for correlations between these STS asymmetries, and find associations mainly between measurements of the same type (e.g., two morphological measurements). Finally, we ask if STS asymmetry is preferentially related to Broca asymmetry, as these are both important language regions and connected via the arcuate fasciculus. Using a linear model with cross-validation, we find that random regions are as successful as Broca's area in predicting STS, and no indication of a hypothesized leftward asymmetry. We conclude that although these different STS asymmetries are robust across datasets, they are not trivially related to each other, suggesting different biological or imaging sources for different aspects of STS lateralities.

Internet addiction associated with right pars opercularis in females.

BACKGROUND AND AIMS: Structural differences in higher-order brain areas are common features of behavioral addictions, including Internet addiction (IA) as well. Taking into consideration the limited number of studies and methods used in previous studies on IA, our aim was to investigate the correlates of IA and the morphometry of the frontal lobes. METHODS: To observe these relationships, the high-resolution T1-weighted MR images of 144 healthy, Caucasian, university students were analyzed with volumetry and voxel-based morphometry. The Problematic Internet Use Questionnaire (PIUQ) was used to assess IA. RESULTS: We found significant correlations between PIUQ subscales and the volume of the right pars opercularis volume and gray matter mass in women. DISCUSSION AND CONCLUSION: The increased gray matter measures of this structure might be explained with the extended effort to control for the impulsive behavior in addiction, and with the increased number of social interactions via the Internet.

El Área del Lenguaje Articulado, Perspectiva Histórica y Denominación Epónima Equívoca: Entre Dax y Broca / Articulated Language Area, Historical Perspective and Erroneous Epomy: Between Dax and Broca

El término epónimo área de Broca corresponde a una región cortical cerebral humana dedicada a la expresión del lenguaje oral y que no siempre se ubica en el giro frontal inferior del lobo frontal en el hemisferio izquierdo. Al estudiar 25 artículos del año 2022 y 25 libros de enseñanza de la neuroanatomía, neurofisiología, neurociencia o áreas asociadas del presente siglo, se estableció y cuantificó la existencia del término área de Broca encontrándose que en los libros había un 96 % de inclusión epónima sobre esta área cortical cerebral y en artículos de revista existía un 100 % del mismo epónimo, además, en ninguno de los libros y artículos se encontró un epónimo diferente. Aunque a lo largo del tiempo, en las ciencias médicas se han usado epónimos para designar estructuras anatómicas como en el caso para tratar de designar el área del cerebro que genera el lenguaje oral, este término no proporciona ninguna información descriptiva ni funcional, lo que equivale a un desatino en la lógica del pensamiento morfológico actual, además que lleva a confusión, pues hace pensar que su descubrimiento inicial fue dado por Broca, equivocando el conocimiento histórico que vincula a Marc Dax como el primero en descubrir esta zona.

SUMMARY: The eponymous Broca's area is a human cerebral cortical region that controls the expression of oral language, and which is not always located in the inferior frontal gyrus of the frontal lobe in the left hemisphere. In a study of 25 articles published in 2022, and 25 teaching books on neuroanatomy, neurophysiology, neuroscience or associated areas, it was found that the term Broca's area was established and quantified. In books there was a 96 % eponymous inclusion of this cerebral cortical area and in journal articles there was 100 % of the same eponym. Furthermore, no other eponyms were found in any of the books and articles. Although over time, eponyms have been used in medical sciences to identify anatomical structures, as in the designation of the area in the brain that controls oral language, this term does not provide any descriptive or functional information. The result is contradictory to current morphological thought and also leads to confusion, erroneously suggesting that the initial discovery was made by Broca, when in fact Marc Dax was the first to discover this area some 30 years earlier.

The error of Broca: From the traditional localizationist concept to a connectomal anatomy of human brain.

Neurology, especially aphasiology, was mainly built on behavioral-structural correlations ("lesion method"). In this setting, Broca's area has been considered as the "speech area"; moreover, this observation led to localizationism. However, advances in brain mapping techniques, as functional neuroimaging and direct electrical stimulation in patients undergoing awake surgery for gliomas, has resulted in a paradigmatic shift regarding models of neural architecture. In fact, the brain is organized in distributed complex networks underpinning sensorimotor, visuospatial, language, cognitive and emotional functions. In this connectomal workframe, cerebral processing is not conceived as the sum of segregated subfunctions, but results from the integration and potentiation of parallel (even if partially overlapped) subcircuits. Such a networking model, taking into account cortical and subcortical anatomic constraints, explains interindividual variability in physiology and after brain damage, particularly in aphasiology - e.g. double dissociations during electrostimulations, as comprehension versus naming disorders, semantic versus phonemic paraphasias, or syntactic disturbances versus anomia. This dynamic organization mediated by the well-synchronized functioning of delocalized groups of interconnected neurons (rather than by discrete centers) also explains the huge potential of neuroplasticity following cerebral insult, on the condition that the axonal connectivity is preserved. According to this principle, massive surgical resection of brain regions dogmatically considered as "critical" in a localisationist view can be achieved with no functional deficit, as the removal of Broca's area - which is not the speech area - without disorders. This connectomal account of neural processing may have major implications in cognitive neurosciences and in therapeutic management of brain-damaged patients.

[Syntactic Processing in Broca's Area: Brodmann Areas 44 and 45].

Brodmann areas 44 and 45 are known as Broca's area; however, their true functional roles are still unknown. Recent developments in neuroimaging techniques revealed the structures and functions of Broca's area in detail. More specifically regarding language functions, sufficient evidence has been accumulated that this region subserves the center of syntactic processing, not necessarily motor functions. Here, we review a role of Broca's area as the grammar center, including other roles in nonlinguistic functions.

Motor skill for tool-use is associated with asymmetries in Broca's area and the motor hand area of the precentral gyrus in chimpanzees (Pan troglodytes).

Among nonhuman primates, chimpanzees are well known for their sophistication and diversity of tool use in both captivity and the wild. The evolution of tool manufacture and use has been proposed as a driving mechanism for the development of increasing brain size, complex cognition and motor skills, as well as the population-level handedness observed in modern humans. Notwithstanding, our understanding of the neurological correlates of tool use in chimpanzees and other primates remains poorly understood. Here, we assessed the hand preference and performance skill of chimpanzees on a tool use task and correlated these data with measures of neuroanatomical asymmetries in the inferior frontal gyrus (IFG) and the pli-de-passage fronto-parietal moyen (PPFM). The IFG is the homolog to Broca's area in the chimpanzee brain and the PPFM is a buried gyrus that connects the pre- and post-central gyri and corresponds to the motor-hand area of the precentral gyrus. We found that chimpanzees that performed the task better with their right compared to left hand showed greater leftward asymmetries in the IFG and PPFM. This association between hand performance and PPFM asymmetry was particularly robust for right-handed individuals. Based on these findings, we propose that the evolution of tool use was associated with increased left hemisphere specialization for motor skill. We further suggest that lateralization in motor planning, rather than hand preference per se, was selected for with increasing tool manufacture and use in Hominid evolution.

Should Broca's area include Brodmann area 47?

BACKGROUND: Understanding brain organization of speech production has been a principal goal of neuroscience. Historically, brain speech production has been associated with so-called Broca's area (Brodmann area ­BA- 44 and 45), however, modern neuroimaging developments suggest speech production is associated with networks rather than with areas. The purpose of this paper was to analyze the connectivity of BA47 ( pars orbitalis) in relation to language . METHOD: A meta-analysis was conducted to assess the language network in which BA47 is involved. The Brainmap database was used. Twenty papers corresponding to 29 experimental conditions with a total of 373 subjects were included. RESULTS: Our results suggest that BA47 participates in a "frontal language production system" (or extended Broca's system). The BA47  connectivity found is also concordant with a minor role in language semantics. CONCLUSIONS: BA47 plays a central role in the language production system.

Broca and Wernicke are dead, or moving past the classic model of language neurobiology.

With the advancement of cognitive neuroscience and neuropsychological research, the field of language neurobiology is at a cross-roads with respect to its framing theories. The central thesis of this article is that the major historical framing model, the Classic "Wernicke-Lichtheim-Geschwind" model, and associated terminology, is no longer adequate for contemporary investigations into the neurobiology of language. We argue that the Classic model (1) is based on an outdated brain anatomy; (2) does not adequately represent the distributed connectivity relevant for language, (3) offers a modular and "language centric" perspective, and (4) focuses on cortical structures, for the most part leaving out subcortical regions and relevant connections. To make our case, we discuss the issue of anatomical specificity with a focus on the contemporary usage of the terms "Broca's and Wernicke's area", including results of a survey that was conducted within the language neurobiology community. We demonstrate that there is no consistent anatomical definition of "Broca's and Wernicke's Areas", and propose to replace these terms with more precise anatomical definitions. We illustrate the distributed nature of the language connectome, which extends far beyond the single-pathway notion of arcuate fasciculus connectivity established in Geschwind's version of the Classic Model. By illustrating the definitional confusion surrounding "Broca's and Wernicke's areas", and by illustrating the difficulty integrating the emerging literature on perisylvian white matter connectivity into this model, we hope to expose the limits of the model, argue for its obsolescence, and suggest a path forward in defining a replacement.

Plasticity of white matter connectivity in phonetics experts.

Phonetics experts are highly trained to analyze and transcribe speech, both with respect to faster changing, phonetic features, and to more slowly changing, prosodic features. Previously we reported that, compared to non-phoneticians, phoneticians had greater local brain volume in bilateral auditory cortices and the left pars opercularis of Broca's area, with training-related differences in the grey-matter volume of the left pars opercularis in the phoneticians group (Golestani et al. 2011). In the present study, we used diffusion MRI to examine white matter microstructure, indexed by fractional anisotropy, in (1) the long segment of arcuate fasciculus (AF_long), which is a well-known language tract that connects Broca's area, including left pars opercularis, to the temporal cortex, and in (2) the fibers arising from the auditory cortices. Most of these auditory fibers belong to three validated language tracts, namely to the AF_long, the posterior segment of the arcuate fasciculus and the middle longitudinal fasciculus. We found training-related differences in phoneticians in left AF_long, as well as group differences relative to non-experts in the auditory fibers (including the auditory fibers belonging to the left AF_long). Taken together, the results of both studies suggest that grey matter structural plasticity arising from phonetic transcription training in Broca's area is accompanied by changes to the white matter fibers connecting this very region to the temporal cortex. Our findings suggest expertise-related changes in white matter fibers connecting fronto-temporal functional hubs that are important for phonetic processing. Further studies can pursue this hypothesis by examining the dynamics of these expertise related grey and white matter changes as they arise during phonetic training.

Contemporary model of language organization: an overview for neurosurgeons.

Classic models of language organization posited that separate motor and sensory language foci existed in the inferior frontal gyrus (Broca's area) and superior temporal gyrus (Wernicke's area), respectively, and that connections between these sites (arcuate fasciculus) allowed for auditory-motor interaction. These theories have predominated for more than a century, but advances in neuroimaging and stimulation mapping have provided a more detailed description of the functional neuroanatomy of language. New insights have shaped modern network-based models of speech processing composed of parallel and interconnected streams involving both cortical and subcortical areas. Recent models emphasize processing in "dorsal" and "ventral" pathways, mediating phonological and semantic processing, respectively. Phonological processing occurs along a dorsal pathway, from the posterosuperior temporal to the inferior frontal cortices. On the other hand, semantic information is carried in a ventral pathway that runs from the temporal pole to the basal occipitotemporal cortex, with anterior connections. Functional MRI has poor positive predictive value in determining critical language sites and should only be used as an adjunct for preoperative planning. Cortical and subcortical mapping should be used to define functional resection boundaries in eloquent areas and remains the clinical gold standard. In tracing the historical advancements in our understanding of speech processing, the authors hope to not only provide practicing neurosurgeons with additional information that will aid in surgical planning and prevent postoperative morbidity, but also underscore the fact that neurosurgeons are in a unique position to further advance our understanding of the anatomy and functional organization of language.