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Ozernov-Palchik O, O'Brien AM, Lee EJ, Richardson H, Romeo R, Lipkin B, Small H, Capella J, Nieto-Castañón A, Saxe R, Gabrieli JDE, Fedorenko E. Precision fMRI reveals that the language network exhibits adult-like left-hemispheric lateralization by 4 years of age. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.15.594172. [PMID: 38798360 PMCID: PMC11118489 DOI: 10.1101/2024.05.15.594172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Left hemisphere damage in adulthood often leads to linguistic deficits, but many cases of early damage leave linguistic processing preserved, and a functional language system can develop in the right hemisphere. To explain this early apparent equipotentiality of the two hemispheres for language, some have proposed that the language system is bilateral during early development and only becomes left-lateralized with age. We examined language lateralization using functional magnetic resonance imaging with two large pediatric cohorts (total n=273 children ages 4-16; n=107 adults). Strong, adult-level left-hemispheric lateralization (in activation volume and response magnitude) was evident by age 4. Thus, although the right hemisphere can take over language function in some cases of early brain damage, and although some features of the language system do show protracted development (magnitude of language response and strength of inter-regional correlations in the language network), the left-hemisphere bias for language is robustly present by 4 years of age. These results call for alternative accounts of early equipotentiality of the two hemispheres for language. Significance Statement Language is the most canonical function that shows a strong hemispheric asymmetry in adult brains. However, whether the language system is already lateralized to the left hemisphere early in development has long been debated, given that early left-hemisphere damage often leaves language processing unimpaired. We examined the developmental trajectory of language lateralization in two large-scale pediatric datasets using robust individual-subject fMRI approaches. We found that the language system exhibits adult-like left-hemispheric lateralization by age 4, although other aspects of the neural infrastructure for language show a clear change between age 4 and late childhood. These findings challengethe claim that the language system is bilateral during early development and call for alternative accounts of early hemispheric equipotentiality for language.
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Shain C, Kean H, Casto C, Lipkin B, Affourtit J, Siegelman M, Mollica F, Fedorenko E. Distributed Sensitivity to Syntax and Semantics throughout the Language Network. J Cogn Neurosci 2024; 36:1427-1471. [PMID: 38683732 DOI: 10.1162/jocn_a_02164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Human language is expressive because it is compositional: The meaning of a sentence (semantics) can be inferred from its structure (syntax). It is commonly believed that language syntax and semantics are processed by distinct brain regions. Here, we revisit this claim using precision fMRI methods to capture separation or overlap of function in the brains of individual participants. Contrary to prior claims, we find distributed sensitivity to both syntax and semantics throughout a broad frontotemporal brain network. Our results join a growing body of evidence for an integrated network for language in the human brain within which internal specialization is primarily a matter of degree rather than kind, in contrast with influential proposals that advocate distinct specialization of different brain areas for different types of linguistic functions.
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Affiliation(s)
| | - Hope Kean
- Massachusetts Institute of Technology
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Fedorenko E, Ivanova AA, Regev TI. The language network as a natural kind within the broader landscape of the human brain. Nat Rev Neurosci 2024; 25:289-312. [PMID: 38609551 DOI: 10.1038/s41583-024-00802-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2024] [Indexed: 04/14/2024]
Abstract
Language behaviour is complex, but neuroscientific evidence disentangles it into distinct components supported by dedicated brain areas or networks. In this Review, we describe the 'core' language network, which includes left-hemisphere frontal and temporal areas, and show that it is strongly interconnected, independent of input and output modalities, causally important for language and language-selective. We discuss evidence that this language network plausibly stores language knowledge and supports core linguistic computations related to accessing words and constructions from memory and combining them to interpret (decode) or generate (encode) linguistic messages. We emphasize that the language network works closely with, but is distinct from, both lower-level - perceptual and motor - mechanisms and higher-level systems of knowledge and reasoning. The perceptual and motor mechanisms process linguistic signals, but, in contrast to the language network, are sensitive only to these signals' surface properties, not their meanings; the systems of knowledge and reasoning (such as the system that supports social reasoning) are sometimes engaged during language use but are not language-selective. This Review lays a foundation both for in-depth investigations of these different components of the language processing pipeline and for probing inter-component interactions.
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Affiliation(s)
- Evelina Fedorenko
- Brain and Cognitive Sciences Department, Massachusetts Institute of Technology, Cambridge, MA, USA.
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
- The Program in Speech and Hearing in Bioscience and Technology, Harvard University, Cambridge, MA, USA.
| | - Anna A Ivanova
- School of Psychology, Georgia Institute of Technology, Atlanta, GA, USA
| | - Tamar I Regev
- Brain and Cognitive Sciences Department, Massachusetts Institute of Technology, Cambridge, MA, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
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Vin R, Blauch NM, Plaut DC, Behrmann M. Visual word processing engages a hierarchical, distributed, and bilateral cortical network. iScience 2024; 27:108809. [PMID: 38303718 PMCID: PMC10831251 DOI: 10.1016/j.isci.2024.108809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 12/20/2023] [Accepted: 01/02/2024] [Indexed: 02/03/2024] Open
Abstract
Although the Visual Word Form Area (VWFA) in left temporal cortex is considered the pre-eminent region in visual word processing, other regions are also implicated. We examined the entire text-selective circuit, using functional MRI. Ten regions of interest (ROIs) per hemisphere were defined, which, based on clustering, grouped into early vision, high-level vision, and language clusters. We analyzed the responses of the ROIs and clusters to words, inverted words, and consonant strings using univariate, multivariate, and functional connectivity measures. Bilateral modulation by stimulus condition was evident, with a stronger effect in left hemisphere regions. Last, using graph theory, we observed that the VWFA was equivalently connected with early visual and language clusters in both hemispheres, reflecting its role as a mediator in the circuit. Although the individual ROIs and clusters bilaterally were flexibly altered by the nature of the input, stability held at the level of global circuit connectivity, reflecting the complex hierarchical distributed system serving visual text perception.
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Affiliation(s)
- Raina Vin
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Nicholas M. Blauch
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Program in Neural Computation, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - David C. Plaut
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Marlene Behrmann
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15219, USA
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Granovetter MC, Maallo AMS, Patterson C, Glen D, Behrmann M. Morphometrics of the preserved post-surgical hemisphere in pediatric drug-resistant epilepsy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.24.559189. [PMID: 37808659 PMCID: PMC10557613 DOI: 10.1101/2023.09.24.559189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Importance Structural integrity of cortex following cortical resection for epilepsy management has been previously characterized, but only in adult patients. Objective This study sought to determine whether morphometrics of the preserved hemisphere in pediatric cortical resection patients differ from non-neurological controls. Design This was a case-control study, from 2013-2022. Setting This was a single-site study. Participants 32 patients with childhood epilepsy surgery and 51 age- and gender-matched controls participated. Main Measures We quantified morphometrics of the preserved hemisphere at the level of gross anatomy (lateral ventricle size, volume of gray and white matter). Additionally, cortical thickness, volume, and surface area were measured for 34 cortical regions segmented with the Desikan-Killiany atlas, and, last, volumes of nine subcortical regions were also quantified. Results 13 patients with left hemisphere (LH) surgery and a preserved right hemisphere (RH) (median age/median absolute deviation of age: 15.7/1.7 yr; 6 females, 7 males) and 19 patients with RH surgery and a preserved LH (15.4/3.7 yr; 11 females, 8 males) were compared to 51 controls (14.8/4.9 yr; 24 females, 27 males). Patient groups had larger ventricles and reduced total white matter volume relative to controls, and only patients with a preserved RH, but not patients with a preserved LH, had reduced total gray matter volume relative to controls. Furthermore, patients with a preserved RH had lower cortical thickness and volume and greater surface area of several cortical regions, relative to controls. Patients with a preserved LH had no differences in thickness, volume, or area, of any of the 34 cortical regions, relative to controls. Moreover, both LH and RH patients showed reduced volumes in select subcortical structures, relative to controls. Conclusions and Relevance That left-sided, but not right-sided, resection is associated with more pronounced reduction in cortical thickness and volume and increased cortical surface area relative to typically developing, age-matched controls suggests that the preserved RH undergoes structural plasticity to an extent not observed in cases of right-sided pediatric resection. Future work probing the association of the current findings with neuropsychological outcomes will be necessary to understand the implications of these structural findings for clinical practice.
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Affiliation(s)
- Michael C. Granovetter
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA 15213
- School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA 15213
| | - Anne Margarette S. Maallo
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA 15213
| | - Christina Patterson
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, USA 15213
| | - Daniel Glen
- Scientific and Statistical Computing Core, National Institute of Mental Health, Bethesda, MD, USA 20892
| | - Marlene Behrmann
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA 15213
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA 15213
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Martin KC, Seydell-Greenwald A, Turkeltaub PE, Chambers CE, Giannetti M, Dromerick AW, Carpenter JL, Berl MM, Gaillard WD, Newport EL. One right can make a left: sentence processing in the right hemisphere after perinatal stroke. Cereb Cortex 2023; 33:11257-11268. [PMID: 37859521 PMCID: PMC10690853 DOI: 10.1093/cercor/bhad362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 09/08/2023] [Indexed: 10/21/2023] Open
Abstract
When brain regions that are critical for a cognitive function in adulthood are irreversibly damaged at birth, what patterns of plasticity support the successful development of that function in an alternative location? Here we investigate the consistency of language organization in the right hemisphere (RH) after a left hemisphere (LH) perinatal stroke. We analyzed fMRI data collected during an auditory sentence comprehension task on 14 people with large cortical LH perinatal arterial ischemic strokes (left hemisphere perinatal stroke (LHPS) participants) and 11 healthy sibling controls using a "top voxel" approach that allowed us to compare the same number of active voxels across each participant and in each hemisphere for controls. We found (1) LHPS participants consistently recruited the same RH areas that were a mirror-image of typical LH areas, and (2) the RH areas recruited in LHPS participants aligned better with the strongly activated LH areas of the typically developed brains of control participants (when flipped images were compared) than the weakly activated RH areas. Our findings suggest that the successful development of language processing in the RH after a LH perinatal stroke may in part depend on recruiting an arrangement of frontotemporal areas reflective of the typical dominant LH.
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Affiliation(s)
- Kelly C Martin
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
| | - Anna Seydell-Greenwald
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
- MedStar National Rehabilitation Hospital, Washington, DC 20010, United States
| | - Peter E Turkeltaub
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
- MedStar National Rehabilitation Hospital, Washington, DC 20010, United States
| | - Catherine E Chambers
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
- MedStar National Rehabilitation Hospital, Washington, DC 20010, United States
| | - Margot Giannetti
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
- MedStar National Rehabilitation Hospital, Washington, DC 20010, United States
| | - Alexander W Dromerick
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
- MedStar National Rehabilitation Hospital, Washington, DC 20010, United States
| | - Jessica L Carpenter
- Division of Pediatric Neurology, Departments of Pediatrics and Neurology, University of Maryland School of Medicine, Baltimore MD 21201, United States
| | - Madison M Berl
- Children’s National Hospital and Center for Neuroscience, Washington, DC 20010, United States
| | - William D Gaillard
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
- Children’s National Hospital and Center for Neuroscience, Washington, DC 20010, United States
| | - Elissa L Newport
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
- MedStar National Rehabilitation Hospital, Washington, DC 20010, United States
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Shain C, Paunov A, Chen X, Lipkin B, Fedorenko E. No evidence of theory of mind reasoning in the human language network. Cereb Cortex 2023; 33:6299-6319. [PMID: 36585774 PMCID: PMC10183748 DOI: 10.1093/cercor/bhac505] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 01/01/2023] Open
Abstract
Language comprehension and the ability to infer others' thoughts (theory of mind [ToM]) are interrelated during development and language use. However, neural evidence that bears on the relationship between language and ToM mechanisms is mixed. Although robust dissociations have been reported in brain disorders, brain activations for contrasts that target language and ToM bear similarities, and some have reported overlap. We take another look at the language-ToM relationship by evaluating the response of the language network, as measured with fMRI, to verbal and nonverbal ToM across 151 participants. Individual-participant analyses reveal that all core language regions respond more strongly when participants read vignettes about false beliefs compared to the control vignettes. However, we show that these differences are largely due to linguistic confounds, and no such effects appear in a nonverbal ToM task. These results argue against cognitive and neural overlap between language processing and ToM. In exploratory analyses, we find responses to social processing in the "periphery" of the language network-right-hemisphere homotopes of core language areas and areas in bilateral angular gyri-but these responses are not selectively ToM-related and may reflect general visual semantic processing.
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Affiliation(s)
- Cory Shain
- Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, MIT Bldg 46-316077 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Alexander Paunov
- INSERM-CEA Cognitive Neuroimaging Unit (UNICOG), NeuroSpin Center, Gif sur Yvette 91191, France
| | - Xuanyi Chen
- Department of Cognitive Sciences, Rice University, 6100 Main Street, Houston, TX 77005, United States
| | - Benjamin Lipkin
- Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, MIT Bldg 46-316077 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Evelina Fedorenko
- Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, MIT Bldg 46-316077 Massachusetts Avenue, Cambridge, MA 02139, United States
- Program in Speech Hearing in Bioscience and Technology, Harvard Medical School, 260 Longwood Avenue, TMEC 333, Boston, MA 02115, United States
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Chupina I, Sierpowska J, Zheng XY, Dewenter A, Piastra M, Piai V. Time course of right-hemisphere recruitment during word production following left-hemisphere damage: A single case of young stroke. Eur J Neurosci 2022; 56:5235-5259. [PMID: 36028218 PMCID: PMC9826534 DOI: 10.1111/ejn.15813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 08/19/2022] [Accepted: 08/25/2022] [Indexed: 01/11/2023]
Abstract
Our understanding of post-stroke language function is largely based on older age groups, who show increasing age-related brain pathology and neural reorganisation. To illustrate language outcomes in the young-adult brain, we present the case of J., a 23-year-old woman with chronic aphasia from a left-hemisphere stroke affecting the temporal lobe. Diffusion MRI-based tractography indicated that J.'s language-relevant white-matter structures were severely damaged. Employing magnetoencephalography (MEG), we explored J.'s conceptual preparation and word planning abilities using context-driven and bare picture-naming tasks. These revealed naming deficits, manifesting as word-finding difficulties and semantic paraphasias about half of the time. Naming was however facilitated by semantically constraining lead-in sentences. Altogether, this pattern indicates disrupted lexical-semantic and phonological retrieval abilities. MEG revealed that J.'s conceptual and naming-related neural responses were supported by the right hemisphere, compared to the typical left-lateralised brain response of a matched control. Differential recruitment of right-hemisphere structures (330-440 ms post-picture onset) was found concurrently during successful naming (right mid-to-posterior temporal lobe) and word-finding attempts (right inferior frontal gyrus). Disconnection of the temporal lobes via corpus callosum was not critical for recruitment of the right hemisphere in visually guided naming, possibly due to neural activity right lateralising from the outset. Although J.'s right hemisphere responded in a timely manner during word planning, its lexical and phonological retrieval abilities remained modest.
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Affiliation(s)
- Irina Chupina
- Donders Centre for CognitionRadboud UniversityNijmegenThe Netherlands
| | - Joanna Sierpowska
- Donders Centre for CognitionRadboud UniversityNijmegenThe Netherlands,Cognition and Brain Plasticity Unit, Department of Cognition, Development and Educational PsychologyInstitut de Neurociències, Universitat de BarcelonaBarcelonaSpain
| | - Xiaochen Y. Zheng
- Donders Centre for Cognitive NeuroimagingRadboud UniversityNijmegenThe Netherlands
| | - Anna Dewenter
- Institute for Stroke and Dementia Research (ISD)University Hospital, LMU MunichMunichGermany
| | - Maria‐Carla Piastra
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and BehaviourRadboud University Medical CenterNijmegenThe Netherlands,Department of Neuroinformatics, Donders Institute for Brain, Cognition and BehaviourRadboud UniversityNijmegenThe Netherlands,Clinical Neurophysiology, Technical Medical Centre, Faculty of Science and TechnologyUniversity of TwenteEnschedeThe Netherlands
| | - Vitória Piai
- Donders Centre for CognitionRadboud UniversityNijmegenThe Netherlands,Department of Medical Psychology, Donders Centre for Medical NeuroscienceRadboud University Medical CenterNijmegenThe Netherlands
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