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Yang M, Liu L, Cui H, Deng C, Xiong W, Zhao G, Du S, Kosten TR, Chen H, Li Z, Zhang X. Dynamic functional thalamocortical dysconnectivity in schizophrenia correlates to antipsychotics response. SCHIZOPHRENIA (HEIDELBERG, GERMANY) 2023; 9:40. [PMID: 37402747 DOI: 10.1038/s41537-023-00371-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 06/26/2023] [Indexed: 07/06/2023]
Abstract
Although many studies have showed abnormal thalamocortical networks in patients with schizophrenia (SCZ), the dynamic functional thalamocortical connectivity of individuals with SCZ and the effect of antipsychotics on this connectivity have not been investigated. Drug-naïve first-episode individuals with SCZ and healthy controls were recruited. Patients were treated with risperidone for 12 weeks. Resting-state functional magnetic resonance imaging was acquired at baseline and week 12. We identified six functional thalamic subdivisions. The sliding window strategy was used to determine the dynamic functional connectivity (dFC) of each functional thalamic subdivision. Individuals with SCZ displayed decreased or increased dFC variance in different thalamic subdivisions. The baseline dFC between ventral posterior-lateral (VPL) portions and right dorsolateral superior frontal gyrus (rdSFG) correlated with psychotic symptoms. The dFC variance between VPL and right medial orbital superior frontal gyrus (rmoSFG) or rdSFG decreased after 12-week risperidone treatment. The decreased dFC variance between VPL and rmoSFG correlated with the reduction of PANSS scores. Interestingly, the dFC between VPL and rmoSFG or rdSFG decreased in responders. The dFC variance change of VPL and the averaged whole brain signal correlated with the risperidone efficacy. Our study demonstrates abnormal variability in thalamocortical dFC may be implicated in psychopathological symptoms and risperidone response in individuals with schizophrenia, suggesting that thalamocortical dFC variance may be correlated to the efficacy of antipsychotic treatment.Registration: ClinicalTrials.gov Identifier: NCT00435370. https://www.clinicaltrials.gov/ct2/show/NCT00435370?term=NCT00435370&draw=2&rank=1.
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Affiliation(s)
- Mi Yang
- The fourth people's hospital of Chengdu, Chengdu, China
| | - Liju Liu
- MOE Key Laboratory for Neuroinformation, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu, China
| | - Hongmei Cui
- Qingdao Mental Health Center, Qingdao University, Qingdao, China
| | - Chijun Deng
- MOE Key Laboratory for Neuroinformation, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu, China
| | - Weisen Xiong
- MOE Key Laboratory for Neuroinformation, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu, China
| | - Guocheng Zhao
- The fourth people's hospital of Chengdu, Chengdu, China
| | - Shulin Du
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Thomas R Kosten
- Department of Psychiatry, Baylor College of Medicine, Houston, TX, USA.
- Epidemiology and Behavioral Science, MD Anderson Cancer Center, Houston, TX, USA.
| | - Huafu Chen
- MOE Key Laboratory for Neuroinformation, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu, China.
- Sichuan Provincial Center for Mental Health, The Center of Psychosomatic Medicine of Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.
| | - Zezhi Li
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China.
| | - Xiangyang Zhang
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China.
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.
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Bertino S, Basile GA, Bramanti A, Ciurleo R, Tisano A, Anastasi GP, Milardi D, Cacciola A. Ventral intermediate nucleus structural connectivity-derived segmentation: anatomical reliability and variability. Neuroimage 2021; 243:118519. [PMID: 34461233 DOI: 10.1016/j.neuroimage.2021.118519] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 07/24/2021] [Accepted: 08/25/2021] [Indexed: 12/30/2022] Open
Abstract
The Ventral intermediate nucleus (Vim) of thalamus is the most targeted structure for the treatment of drug-refractory tremors. Since methodological differences across existing studies are remarkable and no gold-standard pipeline is available, in this study, we tested different parcellation pipelines for tractography-derived putative Vim identification. Thalamic parcellation was performed on a high quality, multi-shell dataset and a downsampled, clinical-like dataset using two different diffusion signal modeling techniques and two different voxel classification criteria, thus implementing a total of four parcellation pipelines. The most reliable pipeline in terms of inter-subject variability has been picked and parcels putatively corresponding to motor thalamic nuclei have been selected by calculating similarity with a histology-based mask of Vim. Then, spatial relations with optimal stimulation points for the treatment of essential tremor have been quantified. Finally, effect of data quality and parcellation pipelines on a volumetric index of connectivity clusters has been assessed. We found that the pipeline characterized by higher-order signal modeling and threshold-based voxel classification criteria was the most reliable in terms of inter-subject variability regardless data quality. The maps putatively corresponding to Vim were those derived by precentral and dentate nucleus-thalamic connectivity. However, tractography-derived functional targets showed remarkable differences in shape and sizes when compared to a ground truth model based on histochemical staining on seriate sections of human brain. Thalamic voxels connected to contralateral dentate nucleus resulted to be the closest to literature-derived stimulation points for essential tremor but at the same time showing the most remarkable inter-subject variability. Finally, the volume of connectivity parcels resulted to be significantly influenced by data quality and parcellation pipelines. Hence, caution is warranted when performing thalamic connectivity-based segmentation for stereotactic targeting.
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Affiliation(s)
- Salvatore Bertino
- Brain Mapping Lab, Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Gianpaolo Antonio Basile
- Brain Mapping Lab, Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | | | | | - Adriana Tisano
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Giuseppe Pio Anastasi
- Brain Mapping Lab, Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Demetrio Milardi
- Brain Mapping Lab, Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Alberto Cacciola
- Brain Mapping Lab, Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy.
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Long J, Lu F, Guo X, Pang Y, Yang S, Chen H, He B. Parcellation of the thalamus by using a dual-segment method based on resting-state functional connectivity: An application on autism spectrum disorder. Neurosci Lett 2020; 742:135518. [PMID: 33246029 DOI: 10.1016/j.neulet.2020.135518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/27/2020] [Accepted: 11/18/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND Evidence suggests thalamus is a key "information relay" center and all cortical areas receive inputs from the thalamus and each of the main nuclei of thalamus connects a single one or a few cortical areas. The traditional "winner-takes-all" thalamus parcellation method was then proposed based on this assumption. However, this method is based on the structural segments of the cortex which is not suitable for the functional parcellation of the thalamus. METHOD Here we proposed a dual-segment method for thalamus functional parcellation based on the resting-state fMRI data. The traditional "winner-takes-all" and the proposed dual-segment methods were both applied to the dataset of 76 healthy controls (HCs) and 34 subjects with autism spectrum disorder. RESULTS The results showed that the thalamus was subdivided into two sub-regions by using the dual-segment method: one is located in the dorsomedial part of thalamus which connects the high-level cognitive cortical regions; the other is located in the ventrolateral part of thalamus which connects the low-level sensory cortical areas. The functional connectivity strength between thalamus sub-regions and the corresponding cortical regions based on the dual-segment method was higher than that of results from the traditional "winner-takes-all" method. The thalamo-cortical functional connectivity based on our proposed method also showed higher classification ability to distinguish subjects with autism spectrum disorder from HCs. CONCLUSION Our study will provide a new method for functional thalamus parcellation which might help understand the sub-regions functions of thalamus in neuroscience studies.
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Affiliation(s)
- Jinjin Long
- School of Medicine, Guizhou University, Guizhou, China
| | - Fengmei Lu
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China
| | - Xiaonan Guo
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yajing Pang
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Shanshan Yang
- School of Medicine, Guizhou University, Guizhou, China
| | - Heng Chen
- School of Medicine, Guizhou University, Guizhou, China; Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu, China.
| | - Bifang He
- School of Medicine, Guizhou University, Guizhou, China; Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu, China.
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4
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Oliveira AR, Nunes RG, Figueiredo P, Dias AI, Leal A. Regional White Matter Atrophy Correlates with Spike Activity in Encephalopathy Related to Status Epilepticus During Slow Sleep (ESES) After Early Thalamic Lesions. Brain Topogr 2020; 33:571-585. [PMID: 32653964 DOI: 10.1007/s10548-020-00784-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 06/28/2020] [Indexed: 11/24/2022]
Abstract
Encephalopathy related to Status Epilepticus during slow Sleep (ESES) is an age-related, epileptic syndrome, which associates cognitive/behavioral disturbances with a peculiar pattern of spike activity. One promising line of research is the study of ESES in cases of early thalamic lesions. We studied 7 ESES patients with unilateral thalamic lesions using magnetic resonance imaging to assess regional white matter (WM) and thalamic nuclei volume differences, and long-term electroencephalogram recordings to localize the epileptogenic cortex. N170 event-related potentials were used to demonstrate the dysfunctional character of the WM abnormalities. Diffusion-weighted images in a subset of 4 patients were used to parcellate the thalamus and evaluate volume asymmetries, based on cortical connectivity. Large WM regional atrophy in the hemisphere with the thalamic lesion was associated with both cortical dysfunction and epileptic activity. A correlation was demonstrated between lesions in the pulvinar and the mediodorsal thalamic nuclei and WM atrophy of the corresponding cortical projection areas. We propose that these abnormalities are due to the widespread structural disconnection produced by the thalamic lesions associated to a yet unknown age-dependent factor. Further exploration of WM regional atrophy association with the spike activity in other etiologies could lend support to the cortical disconnection role in ESES genesis.
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Affiliation(s)
- Ana R Oliveira
- ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
| | - Rita G Nunes
- ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Patrícia Figueiredo
- ISR-Lisboa/LARSyS and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Ana I Dias
- Department of Pediatric Neurology, Hospital Dona Estefânia, Lisbon, Portugal
| | - Alberto Leal
- Department of Pediatric Neurology, Hospital Dona Estefânia, Lisbon, Portugal.,Department of Clinical Neurophysiology, Hospital Júlio de Matos, Lisbon, Portugal
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5
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Cognitive impairment in benign multiple sclerosis: a multiparametric structural and functional MRI study. J Neurol 2020; 267:3508-3517. [DOI: 10.1007/s00415-020-10025-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 10/23/2022]
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6
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Gravbrot N, Saranathan M, Pouratian N, Kasoff W. Advanced Imaging and Direct Targeting of the Motor Thalamus and Dentato-Rubro-Thalamic Tract for Tremor: A Systematic Review. Stereotact Funct Neurosurg 2020; 98:220-240. [DOI: 10.1159/000507030] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 02/27/2020] [Indexed: 11/19/2022]
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7
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Tittgemeyer M, Rigoux L, Knösche TR. Cortical parcellation based on structural connectivity: A case for generative models. Neuroimage 2018; 173:592-603. [PMID: 29407457 DOI: 10.1016/j.neuroimage.2018.01.077] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 12/14/2022] Open
Abstract
One of the major challenges in systems neuroscience is to identify brain networks and unravel their significance for brain function -this has led to the concept of the 'connectome'. Connectomes are currently extensively studied in large-scale international efforts at multiple scales, and follow different definitions with respect to their connections as well as their elements. Perhaps the most promising avenue for defining the elements of connectomes originates from the notion that individual brain areas maintain distinct (long-range) connection profiles. These connectivity patterns determine the areas' functional properties and also allow for their anatomical delineation and mapping. This rationale has motivated the concept of connectivity-based cortex parcellation. In the past ten years, non-invasive mapping of human brain connectivity has led to immense advances in the development of parcellation techniques and their applications. Unfortunately, many of these approaches primarily aim for confirmation of well-known, existing architectonic maps and, to that end, unsuitably incorporate prior knowledge and frequently build on circular argumentation. Often, current approaches also tend to disregard the specific apertures of connectivity measurements, as well as the anatomical specificities of cortical areas, such as spatial compactness, regional heterogeneity, inter-subject variability, the multi-scaling nature of connectivity information, and potential hierarchical organisation. From a methodological perspective, however, a useful framework that regards all of these aspects in an unbiased way is technically demanding. In this commentary, we first outline the concept of connectivity-based cortex parcellation and discuss its prospects and limitations in particular with respect to structural connectivity. To improve reliability and efficiency, we then strongly advocate for connectivity-based cortex parcellation as a modelling approach; that is, an approximation of the data based on (model) parameter inference. As such, a parcellation algorithm can be formally tested for robustness -the precision of its predictions can be quantified and statistics about potential generalization of the results can be derived. Such a framework also allows the question of model constraints to be reformulated in terms of hypothesis testing through model selection and offers a formative way to integrate anatomical knowledge in terms of prior distributions.
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Affiliation(s)
| | - Lionel Rigoux
- Max-Planck-Institute for Metabolism Research, Cologne, Germany
| | - Thomas R Knösche
- Max-Planck-Institute for Cognitive and Brain Sciences, Leipzig, Germany
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8
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Jaimes C, Cheng HH, Soul J, Ferradal S, Rathi Y, Gagoski B, Newburger JW, Grant PE, Zöllei L. Probabilistic tractography-based thalamic parcellation in healthy newborns and newborns with congenital heart disease. J Magn Reson Imaging 2017; 47:1626-1637. [PMID: 29080379 DOI: 10.1002/jmri.25875] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 10/03/2017] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Given the central role of the thalamus in motor, sensory, and cognitive development, methods to study emerging thalamocortical connectivity in early infancy are of great interest. PURPOSE To determine the feasibility of performing probabilistic tractography-based thalamic parcellation (PTbTP) in typically developing (TD) neonates and to compare the results with a pilot sample of neonates with congenital heart disease (CHD). STUDY TYPE Institutional Review Board (IRB)-approved cross-sectional study. MODEL We prospectively recruited 20 TD neonates and five CHD neonates (imaged preoperatively). FIELD STRENGTH/SEQUENCE MRI was performed at 3.0T including diffusion-weighted imaging (DWI) and 3D magnetization prepared rapid gradient-echo (MPRAGE). ASSESSMENT A radiologist and trained research assistants segmented the thalamus and seven cortical targets for each hemisphere. Using the thalami as seeds and the cortical labels as targets, FSL library tools were used to generate probabilistic tracts. A Hierarchical Dirichlet Process algorithm was then used for clustering analysis. A radiologist qualitatively assessed the results of clustering. Quantitative analyses were also performed. STATISTICAL TESTS We summarized the demographic data and results of clustering with descriptive statistics. Linear regressions covarying for gestational age were used to compare groups. RESULTS In 17 of 20 TD neonates, we identified five connectivity-determined clusters, which correlate with known thalamic nuclei and subnuclei. In four neonates with CHD we observed a spectrum of abnormalities including fewer and disorganized clusters or small supernumerary clusters (up to seven per thalamus). After covarying for differences in corrected gestational age (cGA), the fractional anisotropy (FA), volume, and normalized thalamic volume were significantly lower in CHD neonates (P < 0.01). DATA CONCLUSIONS Using PTbTP clusters, correlating well with the location and connectivity of known thalamic nuclei, were identified in TD neonates. Differences in thalamic clustering outputs were identified in four neonates with CHD, raising concern for disordered thalamic connectivity. PTbTP is feasible in TD and CHD neonates. Preliminary findings suggest the prenatal origins of altered connectivity in CHD. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2018;47:1626-1637.
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Affiliation(s)
- Camilo Jaimes
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Henry H Cheng
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Janet Soul
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Silvina Ferradal
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston, Massachusetts, USA.,Department of Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Yogesh Rathi
- Laboratory of Mathematics in Imaging, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Borjan Gagoski
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston, Massachusetts, USA
| | - Jane W Newburger
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - P Ellen Grant
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston, Massachusetts, USA.,Department of Radiology, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Lilla Zöllei
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, Massachusetts, USA; all: Harvard Medical School, Boston, Massachusetts, USA
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Deep brain stimulation for childhood dystonia: Is 'where' as important as in 'whom'? Eur J Paediatr Neurol 2017; 21:176-184. [PMID: 28220756 DOI: 10.1016/j.ejpn.2016.10.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 10/03/2016] [Indexed: 01/07/2023]
Abstract
Deep brain stimulation (DBS) has become a mainstay of dystonia management in adulthood. Typically targeting electrode placement in the GPi, sustained improvement in dystonic symptoms are anticipated in adults with isolated genetic dystonias. Dystonia in childhood is more commonly a symptomatic condition, with dystonia frequently expressed on the background of a structurally abnormal brain. Outcomes following DBS in this setting are much more variable, the reasons for which have yet to be elucidated. Much of the focus on improving outcomes following DBS in dystonia management has been on the importance of patient selection, with, until recently, little discussion of the choice of target. In this review, we advance the argument that patient selection for DBS in childhood cannot be made separate from the choice of target nuclei. The anatomy of common DBS targets is considered, and factors influencing their choice for electrode insertion are discussed. We propose an "ABC" for DBS in childhood dystonia is proposed: Appropriate Child selected; Best nuclei chosen for electrode insertion; Correct position within that nucleus.
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10
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Lambert C, Simon H, Colman J, Barrick TR. Defining thalamic nuclei and topographic connectivity gradients in vivo. Neuroimage 2016; 158:466-479. [PMID: 27639355 DOI: 10.1016/j.neuroimage.2016.08.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 08/12/2016] [Accepted: 08/14/2016] [Indexed: 10/21/2022] Open
Abstract
The thalamus consists of multiple nuclei that have been previously defined by their chemoarchitectual and cytoarchitectual properties ex vivo. These form discrete, functionally specialized, territories with topographically arranged graduated patterns of connectivity. However, previous in vivo thalamic parcellation with MRI has been hindered by substantial inter-individual variability or discrepancies between MRI derived segmentations and histological sections. Here, we use the Euclidean distance to characterize probabilistic tractography distributions derived from diffusion MRI. We generate 12 feature maps by performing voxel-wise parameterization of the distance histograms (6 feature maps) and the distribution of three-dimensional distance transition gradients generated by applying a Sobel kernel to the distance metrics. We use these 12 feature maps to delineate individual thalamic nuclei, then extract the tractography profiles for each and calculate the voxel-wise tractography gradients. Within each thalamic nucleus, the tractography gradients were topographically arranged as distinct non-overlapping cortical networks with transitory overlapping mid-zones. This work significantly advances quantitative segmentation of the thalamus in vivo using 3T MRI. At an individual subject level, the thalamic segmentations consistently achieve a close relationship with a priori histological atlas information, and resolve in vivo topographic gradients within each thalamic nucleus for the first time. Additionally, these techniques allow individual thalamic nuclei to be closely aligned across large populations and generate measures of inter-individual variability that can be used to study both basic function and pathological processes in vivo.
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Affiliation(s)
- Christian Lambert
- Neurosciences Research Centre, Cardiac and Cell Sciences Research Institute, St George's University of London, United Kingdom.
| | - Henry Simon
- Neurosciences Research Centre, Cardiac and Cell Sciences Research Institute, St George's University of London, United Kingdom
| | - Jordan Colman
- Neurosciences Research Centre, Cardiac and Cell Sciences Research Institute, St George's University of London, United Kingdom
| | - Thomas R Barrick
- Neurosciences Research Centre, Cardiac and Cell Sciences Research Institute, St George's University of London, United Kingdom
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11
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Pelzer EA, Melzer C, Timmermann L, von Cramon DY, Tittgemeyer M. Basal ganglia and cerebellar interconnectivity within the human thalamus. Brain Struct Funct 2016; 222:381-392. [PMID: 27089884 PMCID: PMC5225161 DOI: 10.1007/s00429-016-1223-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 04/03/2016] [Indexed: 12/26/2022]
Abstract
Basal ganglia and the cerebellum are part of a densely interconnected network. While both subcortical structures process information in basically segregated loops that primarily interact in the neocortex, direct subcortical interaction has been recently confirmed by neuroanatomical studies using viral transneuronal tracers in non-human primate brains. The thalamus is thought to be the main relay station of both projection systems. Yet, our understanding of subcortical basal ganglia and cerebellar interconnectivity within the human thalamus is rather sparse, primarily due to limitation in the acquisition of in vivo tracing. Consequently, we strive to characterize projections of both systems and their potential overlap within the human thalamus by diffusion MRI and tractography. Our analysis revealed a decreasing anterior-to-posterior gradient for pallido-thalamic connections in: (1) the ventral-anterior thalamus, (2) the intralaminar nuclei, and (3) midline regions. Conversely, we found a decreasing posterior-to-anterior gradient for dentato-thalamic projections predominantly in: (1) the ventral-lateral and posterior nucleus; (2) dorsal parts of the intralaminar nuclei and the subparafascicular nucleus, and (3) the medioventral and lateral mediodorsal nucleus. A considerable overlap of connectivity pattern was apparent in intralaminar nuclei and midline regions. Notably, pallidal and cerebellar projections were both hemispherically lateralized to the left thalamus. While strikingly consistent with findings from transneuronal studies in non-human primates as well as with pre-existing anatomical studies on developmentally expressed markers or pathological human brains, our assessment provides distinctive connectional fingerprints that illustrate the anatomical substrate of integrated functional networks between basal ganglia and the cerebellum. Thereby, our findings furnish useful implications for cerebellar contributions to the clinical symptomatology of movement disorders.
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Affiliation(s)
- Esther A Pelzer
- Translational Neurocirciutry Group, Max-Planck Institute for Metabolism Research Cologne, 50931, Cologne, Germany.,Department of Neurology, University Clinics Cologne, Cologne, Germany
| | - Corina Melzer
- Translational Neurocirciutry Group, Max-Planck Institute for Metabolism Research Cologne, 50931, Cologne, Germany
| | - Lars Timmermann
- Department of Neurology, University Clinics Cologne, Cologne, Germany
| | - D Yves von Cramon
- Translational Neurocirciutry Group, Max-Planck Institute for Metabolism Research Cologne, 50931, Cologne, Germany.,Max-Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Marc Tittgemeyer
- Translational Neurocirciutry Group, Max-Planck Institute for Metabolism Research Cologne, 50931, Cologne, Germany.
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12
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Chen H, Uddin LQ, Zhang Y, Duan X, Chen H. Atypical effective connectivity of thalamo-cortical circuits in autism spectrum disorder. Autism Res 2016; 9:1183-1190. [PMID: 27868393 DOI: 10.1002/aur.1614] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/24/2015] [Accepted: 01/20/2016] [Indexed: 12/12/2022]
Abstract
Autism spectrum disorder (ASD) is a neurodevelopment disorder characterized by atypical connectivity within and across multiple brain systems. We aimed to explore information transmission from the sensory periphery to information processing centers of the brain across thalamo-cortical circuits in ASD. A large multicenter dataset from the autism brain imaging data exchange was utilized. A thalamus template derived from the Automatic Anatomic Labeling atlas was subdivided into six subregions corresponding to six cortical regions using a "winner-takes-all" strategy. Granger causality analysis (GCA) was then applied to calculate effective connectivity from subregions of the thalamus to the corresponding cortical regions. Results demonstrate reduced effective connectivity from the thalamus to left prefrontal cortex (P = 0.023), right posterior parietal cortex (P = 0.03), and bilateral temporal cortex (left: P = 0.014; right: P = 0.015) in ASD compared with healthy control (HC) participants. The GCA values of the thalamus-bilateral temporal cortex connections were significantly negatively correlated with communication scores as assessed by the autism diagnostic observation schedule in the ASD group (left: P = 0.037; right: P = 0.007). Age-related analyses showed that the strengths of the thalamus-bilateral temporal cortex connections were significantly positively correlated with age in the HC group (left: P = 0.013; right: P = 0.016), but not in the ASD group (left: P = 0.506; right: P = 0.219). These results demonstrate impaired thalamo-cortical information transmission in ASD and suggest that atypical development of thalamus-temporal cortex connections may relate to communication deficits in the disorder. Autism Res 2016, 9: 1183-1190. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.
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Affiliation(s)
- Heng Chen
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, and Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Lucina Q Uddin
- Department of Psychology, University of Miami, Coral Gables, FL, USA
| | - Youxue Zhang
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, and Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xujun Duan
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, and Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Huafu Chen
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, and Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu, China
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Groupwise connectivity-based parcellation of the whole human cortical surface using watershed-driven dimension reduction. Med Image Anal 2016; 30:11-29. [PMID: 26849421 DOI: 10.1016/j.media.2016.01.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 01/05/2016] [Accepted: 01/07/2016] [Indexed: 12/14/2022]
Abstract
Segregating the human cortex into distinct areas based on structural connectivity criteria is of widespread interest in neuroscience. This paper presents a groupwise connectivity-based parcellation framework for the whole cortical surface using a new high quality diffusion dataset of 79 healthy subjects. Our approach performs gyrus by gyrus to parcellate the whole human cortex. The main originality of the method is to compress for each gyrus the connectivity profiles used for the clustering without any anatomical prior information. This step takes into account the interindividual cortical and connectivity variability. To this end, we consider intersubject high density connectivity areas extracted using a surface-based watershed algorithm. A wide validation study has led to a fully automatic pipeline which is robust to variations in data preprocessing (tracking type, cortical mesh characteristics and boundaries of initial gyri), data characteristics (including number of subjects), and the main algorithmic parameters. A remarkable reproducibility is achieved in parcellation results for the whole cortex, leading to clear and stable cortical patterns. This reproducibility has been tested across non-overlapping subgroups and the validation is presented mainly on the pre- and postcentral gyri.
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Bisecco A, Rocca MA, Pagani E, Mancini L, Enzinger C, Gallo A, Vrenken H, Stromillo ML, Copetti M, Thomas DL, Fazekas F, Tedeschi G, Barkhof F, Stefano ND, Filippi M. Connectivity-based parcellation of the thalamus in multiple sclerosis and its implications for cognitive impairment: A multicenter study. Hum Brain Mapp 2015; 36:2809-25. [PMID: 25873194 DOI: 10.1002/hbm.22809] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/25/2015] [Accepted: 03/25/2015] [Indexed: 11/06/2022] Open
Abstract
In this multicenter study, we performed a tractography-based parcellation of the thalamus and its white matter connections to investigate the relationship between thalamic connectivity abnormalities and cognitive impairment in multiple sclerosis (MS). Dual-echo, morphological and diffusion tensor (DT) magnetic resonance imaging (MRI) scans were collected from 52 relapsing-remitting MS patients and 57 healthy controls from six European centers. Patients underwent an extensive neuropsychological assessment. Thalamic connectivity defined regions (CDRs) were segmented based on their cortical connectivity using diffusion tractography-based parcellation. Between-group differences of CDRs and cortico-thalamic tracts DT MRI indices were assessed. A vertex analysis of thalamic shape was also performed. A random forest analysis was run to identify the best imaging predictor of global cognitive impairment and deficits of specific cognitive domains. Twenty-two (43%) MS patients were cognitively impaired (CI). Compared to cognitively preserved, CI MS patients had increased fractional anisotropy of frontal, motor, postcentral and occipital connected CDRs (0.002<P<0.02). They also experienced more pronounced atrophy in anterior thalamic regions and abnormal DT MRI indices of all cortico-thalamic tracts. Damage of specific cortico-thalamic tracts explained global cognitive dysfunction and impairment of selected cognitive domains better than all other MRI variables. Thalamic CDR DT MRI abnormalities were correlated with abnormalities of the corresponding cortico-thalamic tracts. Cortico-thalamic disconnection is, at various levels, implicated in cognitive dysfunction in MS. Thalamic involvement in CI MS patients is likely related to gray matter rather than white matter damage of thalamic subregions.
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Affiliation(s)
- Alvino Bisecco
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.,I Division of Neurology, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Second University of Naples, Naples, Italy.,MRI Center "SUN-FISM," Second University of Naples and Institute of Diagnosis and Care "Hermitage-Capodimonte,", Naples, Italy
| | - Maria A Rocca
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.,Department of Neurology, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Elisabetta Pagani
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Laura Mancini
- National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK
| | | | - Antonio Gallo
- I Division of Neurology, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Second University of Naples, Naples, Italy.,MRI Center "SUN-FISM," Second University of Naples and Institute of Diagnosis and Care "Hermitage-Capodimonte,", Naples, Italy
| | - Hugo Vrenken
- Department of Radiology and Nuclear Medicine, MS Centre Amsterdam, VU University Medical Centre, Amsterdam, The Netherlands
| | | | - Massimiliano Copetti
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - David L Thomas
- Neuroradiological Academic Unit, UCL Institute of Neurology, Queen Square, London, United Kingdom
| | - Franz Fazekas
- Department of Neurology, Medical University of Graz, Austria
| | - Gioacchino Tedeschi
- I Division of Neurology, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Second University of Naples, Naples, Italy.,MRI Center "SUN-FISM," Second University of Naples and Institute of Diagnosis and Care "Hermitage-Capodimonte,", Naples, Italy
| | - Frederik Barkhof
- Department of Radiology and Nuclear Medicine, MS Centre Amsterdam, VU University Medical Centre, Amsterdam, The Netherlands
| | - Nicola De Stefano
- Department of Neurological and Behavioral Sciences, University of Siena, Italy
| | - Massimo Filippi
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.,Department of Neurology, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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Broser PJ, Moor V, Braun C. A Non-Magnetic Rotating Disk Stimulator for the Study of Neuromagnetic Correlates of Sensorimotor Interaction. IEEE Trans Neural Syst Rehabil Eng 2015; 23:1078-84. [PMID: 25823039 DOI: 10.1109/tnsre.2015.2414482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Fine motor skills in humans require close interaction between the motor and the sensory systems. It is still not fully understood, how sensory feedback modulates motor commands. This is due to the fact, that there is no approach for investigating the sensorimotor cortical-interaction in sufficient detail. The fast and precise communication between the sensory and motor-systems requires measurements of cortical activity with high temporal and spatial resolution. Magnetoencephalography (MEG) is capable of both. Previously, we showed that sensory responses, can be observed by repetitive tactile stimulation. Further, motor cortex responses can be generated by periodical increase and decrease of muscle tone. Utilizing both observations we have designed an MEG and magnetic resonance imaging (MRI) compatible stimulator allowing for the study of brain activity related to sensorimotor integration. The stimulator consists of a rotating disk with an elevation such that subject senses with his finger the speed of the disk. With the force applied by the finger onto the disk, the subject can control its speed. During the experiment the subject is asked to keep the speed of the disk constant while the driving torque is systematically manipulated. This closed-loop design is especially useful to analyze the fast and continuous information flow between the two systems. In a single case pilot study using MEG, we could show that a detailed analysis of the sensorimotor-network is possible. In contrast to existing paradigms this setup allows separate time-locked analysis of the sensory- and motor-component independently and therefore the calculation of latency parameters for both systems. In the future this method will help to understand the interaction between the two systems in much greater detail.
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Philp DJ, Korgaonkar MS, Grieve SM. Thalamic volume and thalamo-cortical white matter tracts correlate with motor and verbal memory performance. Neuroimage 2014; 91:77-83. [PMID: 24401559 DOI: 10.1016/j.neuroimage.2013.12.057] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 12/12/2013] [Accepted: 12/23/2013] [Indexed: 10/25/2022] Open
Abstract
Cognitive testing and diffusion tensor imaging data from 121 normal subjects were combined to investigate the relationship between thalamic connectivity and cognitive performance. Thalamic regions were segmented based on their cortical connectivity, and regions for both ipsilateral and contralateral thalamocortical connections were identified. White matter tracts corresponding to these regions were identified and the mean fractional anisotropy, and axial and radial diffusivities within each tract were measured. Motor task performance correlated with radial diffusivity in the dominant thalamo-precentral tract. Verbal memory corresponded with the thalamic volume connected to the left temporal lobe. These data support the use of diffusion tractography to identify functionally important regions within the thalamus. Our findings provide the first robust correlation between thalamic volumes and tract characteristics with cognitive performance data in normal subjects.
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Affiliation(s)
- David J Philp
- The Brain Dynamics Centre, Sydney Medical School - Westmead, Sydney, NSW 2145, Australia; Westmead Millennium Institute, Westmead, Sydney, NSW 2145, Australia; Sydney Translational Imaging Laboratory, Sydney Medical School, University of Sydney, Camperdown, NSW 2050, Australia
| | - Mayuresh S Korgaonkar
- The Brain Dynamics Centre, Sydney Medical School - Westmead, Sydney, NSW 2145, Australia; Westmead Millennium Institute, Westmead, Sydney, NSW 2145, Australia; Sydney Translational Imaging Laboratory, Sydney Medical School, University of Sydney, Camperdown, NSW 2050, Australia; Discipline of Psychiatry, University of Sydney Medical School: Western, Westmead Hospital, Sydney, NSW 2145, Australia
| | - Stuart M Grieve
- The Brain Dynamics Centre, Sydney Medical School - Westmead, Sydney, NSW 2145, Australia; Westmead Millennium Institute, Westmead, Sydney, NSW 2145, Australia; Sydney Translational Imaging Laboratory, Sydney Medical School, University of Sydney, Camperdown, NSW 2050, Australia; Department of Radiology, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia.
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Changes in the integrity of thalamocortical connections are associated with sensorimotor deficits in children with congenital hemiplegia. Brain Struct Funct 2013; 220:307-18. [DOI: 10.1007/s00429-013-0656-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 10/09/2013] [Indexed: 10/26/2022]
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Mandal PK, Mahajan R, Dinov ID. Structural brain atlases: design, rationale, and applications in normal and pathological cohorts. J Alzheimers Dis 2013; 31 Suppl 3:S169-88. [PMID: 22647262 DOI: 10.3233/jad-2012-120412] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Structural magnetic resonance imaging (MRI) provides anatomical information about the brain in healthy as well as in diseased conditions. On the other hand, functional MRI (fMRI) provides information on the brain activity during performance of a specific task. Analysis of fMRI data requires the registration of the data to a reference brain template in order to identify the activated brain regions. Brain templates also find application in other neuroimaging modalities, such as diffusion tensor imaging and multi-voxel spectroscopy. Further, there are certain differences (e.g., brain shape and size) in the brains of populations of different origin and during diseased conditions like in Alzheimer's disease (AD), population and disease-specific brain templates may be considered crucial for accurate registration and subsequent analysis of fMRI as well as other neuroimaging data. This manuscript provides a comprehensive review of the history, construction and application of brain atlases. A chronological outline of the development of brain template design, starting from the Talairach and Tournoux atlas to the Chinese brain template (to date), along with their respective detailed construction protocols provides the backdrop to this manuscript. The manuscript also provides the automated workflow-based protocol for designing a population-specific brain atlas from structural MRI data using LONI Pipeline graphical workflow environment. We conclude by discussing the scope of brain templates as a research tool and their application in various neuroimaging modalities.
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Affiliation(s)
- Pravat K Mandal
- Neurospectroscopy and Neuroimaging Laboratory, National Brain Research Center, Gurgaon, India.
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Sudhyadhom A, McGregor K, Okun MS, Foote KD, Trinastic J, Crosson B, Bova FJ. Delineation of motor and somatosensory thalamic subregions utilizing probabilistic diffusion tractography and electrophysiology. J Magn Reson Imaging 2012; 37:600-9. [PMID: 23060259 DOI: 10.1002/jmri.23861] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 09/05/2012] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To employ and compare probabilistic diffusion tractography (PDT) for the explicit localization of connections from the thalamus to somatosensory cortex (S1) and primary motor cortex (M1) / supplementary motor area (SMA) with microelectrode electrophysiology in patients undergoing deep brain stimulation (DBS) surgery. MATERIALS AND METHODS These tractography-derived connections were used to categorize voxels in the thalamus as corresponding to sensory or motor physiology. A novel model (referred to in this work as the "mixture" model) to delineate PDT-based thalamic functional subregions by thresholding fiber intensities, ie, connectivity-defined regions (CDR), was devised. Regions created using this classification method were compared with the most commonly used model (referred to in this work as the "separation" or "winner takes all" model) for defining CDRs. RESULTS Electrophysiology data corresponded better for S1 CDRs created using the mixture model for both sensory and motor cells. Separation model CDRs showed poor correspondence against electrophysiology, with few sensory cells corresponding to the S1 separation model CDR. CONCLUSION Mixture model-based CDRs may offer a significant improvement in delineation of functional subregions of subcortical structures.
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Affiliation(s)
- Atchar Sudhyadhom
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0265, USA.
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Cloutman LL, Lambon Ralph MA. Connectivity-based structural and functional parcellation of the human cortex using diffusion imaging and tractography. Front Neuroanat 2012; 6:34. [PMID: 22952459 PMCID: PMC3429885 DOI: 10.3389/fnana.2012.00034] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Accepted: 07/28/2012] [Indexed: 01/17/2023] Open
Abstract
The parcellation of the cortex via its anatomical properties has been an important research endeavor for over a century. To date, however, a universally accepted parcellation scheme for the human brain still remains elusive. In the current review, we explore the use of in vivo diffusion imaging and white matter tractography as a non-invasive method for the structural and functional parcellation of the human cerebral cortex, discussing the strengths and limitations of the current approaches. Cortical parcellation via white matter connectivity is based on the premise that, as connectional anatomy determines functional organization, it should be possible to segregate functionally-distinct cortical regions by identifying similarities and differences in connectivity profiles. Recent studies have provided initial evidence in support of the efficacy of this connectional parcellation methodology. Such investigations have identified distinct cortical subregions which correlate strongly with functional regions identified via fMRI and meta-analyses. Furthermore, a strong parallel between the cortical regions defined via tractographic and more traditional cytoarchitectonic parcellation methods has been observed. However, the degree of correspondence and relative functional importance of cytoarchitectonic- versus connectivity-derived parcellations still remains unclear. Diffusion tractography remains one of the only methods capable of visualizing the structural networks of the brain in vivo. As such, it is of vital importance to continue to improve the accuracy of the methodology and to extend its potential applications in the study of cognition in neurological health and disease.
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Affiliation(s)
- Lauren L Cloutman
- Neuroscience and Aphasia Research Unit, School of Psychological Sciences, University of Manchester Manchester, UK
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Broser PJ, Groeschel S, Hauser TK, Lidzba K, Wilke M. Functional MRI-guided probabilistic tractography of cortico-cortical and cortico-subcortical language networks in children. Neuroimage 2012; 63:1561-70. [PMID: 22884825 DOI: 10.1016/j.neuroimage.2012.07.060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 07/27/2012] [Accepted: 07/28/2012] [Indexed: 10/28/2022] Open
Abstract
In this study, we analyzed the structural connectivity of cortico-cortical and cortico-subcortical language networks in healthy children, using probabilistic tractography based on high angular resolution diffusion imaging. In addition to anatomically defining seed and target regions for tractography, we used fMRI to target inferior frontal and superior temporal cortical language areas on an individual basis. Further, connectivity between these cortical and subcortical (thalamus, caudate nucleus) language regions was assessed. Overall, data from 15 children (8f) aged 8-17 years (mean age 12.1 ±3 years) could be included. A slight but non-significant trend towards leftward lateralization was found in the arcuate fasciculus/superior longitudinal fasciculus (AF/SLF) using anatomically defined masks (p>.05, Wilcoxon rank test), while the functionally-guided tractography showed a significant lateralization to the left (p<.01). Connectivity of the thalamus with language regions was strong but not lateralized. Connectivity of the caudate nucleus with inferior-frontal language regions was also symmetrical, while connectivity with superior-temporal language regions was strongly lateralized to the left (p<.01). To conclude, we could show that tracking the arcuate fasciculus/superior longitudinal fasciculus is possible using both anatomically and functionally-defined seed and target regions. With the latter approach, we could confirm the presence of structurally-lateralized cortico-cortical language networks already in children, and finally, we could demonstrate a strongly asymmetrical connectivity of the caudate nucleus with superior temporal language regions. Further research is necessary in order to assess the usability of such an approach to assess language dominance in children unable to participate in an active fMRI study.
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