scholarly journals Effect of corpus callosum agenesis on the language network in children and adolescents

2021 ◽  
Author(s):  
Lisa Bartha-Doering ◽  
Ernst Schwartz ◽  
Kathrin Kollndorfer ◽  
Florian Ph. S. Fischmeister ◽  
Astrid Novak ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Corpus Callosum ◽  
Network Connectivity ◽  
Functional Language ◽  
Healthy Controls ◽  
Language Abilities ◽  
Verbal Abilities ◽  
Left And Right ◽  
Language Network

AbstractThe present study is interested in the role of the corpus callosum in the development of the language network. We, therefore, investigated language abilities and the language network using task-based fMRI in three cases of complete agenesis of the corpus callosum (ACC), three cases of partial ACC and six controls. Although the children with complete ACC revealed impaired functions in specific language domains, no child with partial ACC showed a test score below average. As a group, ACC children performed significantly worse than healthy controls in verbal fluency and naming. Furthermore, whole-brain ROI-to-ROI connectivity analyses revealed reduced intrahemispheric and right intrahemispheric functional connectivity in ACC patients as compared to controls. In addition, stronger functional connectivity between left and right temporal areas was associated with better language abilities in the ACC group. In healthy controls, no association between language abilities and connectivity was found. Our results show that ACC is associated not only with less interhemispheric, but also with less right intrahemispheric language network connectivity in line with reduced verbal abilities. The present study, thus, supports the excitatory role of the corpus callosum in functional language network connectivity and language abilities.

scholarly journals The role of the corpus callosum in language network connectivity in children

2020 ◽  
Author(s):  
Lisa Bartha-Doering ◽  
Kathrin Kollndorfer ◽  
Ernst Schwartz ◽  
Florian Ph.S. Fischmeister ◽  
Johanna Alexopoulos ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Network Connectivity ◽  
Language Network

scholarly journals Reconfiguration of Directed Functional Connectivity Among Neurocognitive Networks with Aging: Considering the Role of Thalamo-Cortical Interactions

2020 ◽  
Author(s):  
Moumita Das ◽  
Vanshika Singh ◽  
Lucina Q Uddin ◽  
Arpan Banerjee ◽  
Dipanjan Roy
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Large Scale ◽  
Network Connectivity ◽  
Resting State Fmri ◽  
Brain Network ◽  
Fmri Data ◽  
Independent Dataset ◽  
Left And Right

Abstract A complete picture of how subcortical nodes, such as the thalamus, exert directional influence on large-scale brain network interactions across age remains elusive. Using directed functional connectivity and weighted net causal outflow on resting-state fMRI data, we provide evidence of a comprehensive reorganization within and between neurocognitive networks (default mode: DMN, salience: SN, and central executive: CEN) associated with age and thalamocortical interactions. We hypothesize that thalamus subserves both modality-specific and integrative hub role in organizing causal weighted outflow among large-scale neurocognitive networks. To this end, we observe that within-network directed functional connectivity is driven by thalamus and progressively weakens with age. Secondly, we find that age-associated increase in between CEN- and DMN-directed functional connectivity is driven by both the SN and the thalamus. Furthermore, left and right thalami act as a causal integrative hub exhibiting substantial interactions with neurocognitive networks with aging and play a crucial role in reconfiguring network outflow. Notably, these results were largely replicated on an independent dataset of matched young and old individuals. Our findings strengthen the hypothesis that the thalamus is a key causal hub balancing both within- and between-network connectivity associated with age and maintenance of cognitive functioning with aging.

scholarly journals Glutamate connectivity associations converge upon the salience network in schizophrenia and healthy controls

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Robert A. McCutcheon ◽  
Toby Pillinger ◽  
Maria Rogdaki ◽  
Juan Bustillo ◽  
Oliver D. Howes
Keyword(s):  
Functional Connectivity ◽  
Frontal Cortex ◽  
Network Connectivity ◽  
Resonance Spectroscopy ◽  
Salience Network ◽  
Healthy Controls ◽  
1H Mrs ◽  
Before And After ◽  
Functional Brain Networks ◽  
The Relationship

AbstractAlterations in cortical inter-areal functional connectivity, and aberrant glutamatergic signalling are implicated in the pathophysiology of schizophrenia but the relationship between the two is unclear. We used multimodal imaging to identify areas of convergence between the two systems. Two separate cohorts were examined, comprising 195 participants in total. All participants received resting state functional MRI to characterise functional brain networks and proton magnetic resonance spectroscopy (1H-MRS) to measure glutamate concentrations in the frontal cortex. Study A investigated the relationship between frontal cortex glutamate concentrations and network connectivity in individuals with schizophrenia and healthy controls. Study B also used 1H-MRS, and scanned individuals with schizophrenia and healthy controls before and after a challenge with the glutamatergic modulator riluzole, to investigate the relationship between changes in glutamate concentrations and changes in network connectivity. In both studies the network based statistic was used to probe associations between glutamate and connectivity, and glutamate associated networks were then characterised in terms of their overlap with canonical functional networks. Study A involved 76 individuals with schizophrenia and 82 controls, and identified a functional network negatively associated with glutamate concentrations that was concentrated within the salience network (p < 0.05) and did not differ significantly between patients and controls (p > 0.85). Study B involved 19 individuals with schizophrenia and 17 controls and found that increases in glutamate concentrations induced by riluzole were linked to increases in connectivity localised to the salience network (p < 0.05), and the relationship did not differ between patients and controls (p > 0.4). Frontal cortex glutamate concentrations are associated with inter-areal functional connectivity of a network that localises to the salience network. Changes in network connectivity in response to glutamate modulation show an opposite effect compared to the relationship observed at baseline, which may complicate pharmacological attempts to simultaneously correct glutamatergic and connectivity aberrations.

scholarly journals Dynamic Interhemispheric Desynchronization in Marmosets and Humans With Disorders of the Corpus Callosum

2020 ◽  
Vol 14 ◽  
Author(s):  
Diego Szczupak ◽  
Cecil C. Yen ◽  
Cirong Liu ◽  
Xiaoguang Tian ◽  
Roberto Lent ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Corpus Callosum ◽  
Resting State ◽  
Human Subjects ◽  
Healthy Controls ◽  
Resting State Functional Connectivity ◽  
Periodic Patterns ◽  
Lower Strength ◽  
Neuronal Communication ◽  
Clear Explanation

The corpus callosum, the principal structural avenue for interhemispheric neuronal communication, controls the brain’s lateralization. Developmental malformations of the corpus callosum (CCD) can lead to learning and intellectual disabilities. Currently, there is no clear explanation for these symptoms. Here, we used resting-state functional MRI (rsfMRI) to evaluate the dynamic resting-state functional connectivity (rsFC) in both the cingulate cortex (CG) and the sensory areas (S1, S2, A1) in three marmosets (Callithrix jacchus) with spontaneous CCD. We also performed rsfMRI in 10 CCD human subjects (six hypoplasic and four agenesic). We observed no differences in the strength of rsFC between homotopic CG and sensory areas in both species when comparing them to healthy controls. However, in CCD marmosets, we found lower strength of quasi-periodic patterns (QPP) correlation in the posterior interhemispheric sensory areas. We also found a significant lag of interhemispheric communication in the medial CG, suggesting asynchrony between the two hemispheres. Correspondingly, in human subjects, we found that the CG of acallosal subjects had a higher QPP correlation than controls. In comparison, hypoplasic subjects had a lower QPP correlation and a delay of 1.6 s in the sensory regions. These results show that CCD affects the interhemispheric synchrony of both CG and sensory areas and that, in both species, its impact on cortical communication varies along the CC development gradient. Our study shines a light on how CCD misconnects homotopic regions and opens a line of research to explain the causes of the symptoms exhibited by CCD patients and how to mitigate them.

scholarly journals Genetic ( APOE , BDNF ) influences on functional language network connectivity in healthy older adults

2020 ◽  
Vol 16 (S4) ◽  
Author(s):  
Manuela Pietzuch ◽  
Aidan Bindoff ◽  
Francesco Sforazzini ◽  
James C Vickers
Keyword(s):  
Older Adults ◽  
Network Connectivity ◽  
Functional Language ◽  
Healthy Older Adults ◽  
Language Network

scholarly journals Preservation of electrophysiological functional connectivity after partial corpus callosotomy: case report

2018 ◽  
Vol 22 (2) ◽  
pp. 214-219 ◽  
Author(s):  
Kaitlyn Casimo ◽  
Fabio Grassia ◽  
Sandra L. Poliachik ◽  
Edward Novotny ◽  
Andrew Poliakov ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Corpus Callosum ◽  
Seizure Activity ◽  
Diffusion Tensor ◽  
Phase Locking ◽  
Corpus Callosotomy ◽  
Left And Right ◽  
Phase Locking Value ◽  
Anatomical Mri ◽  
Electrophysiological Methods

Prior studies of functional connectivity following callosotomy have disagreed in the observed effects on interhemispheric functional connectivity. These connectivity studies, in multiple electrophysiological methods and functional MRI, have found conflicting reductions in connectivity or patterns resembling typical individuals. The authors examined a case of partial anterior corpus callosum connection, where pairs of bilateral electrocorticographic electrodes had been placed over homologous regions in the left and right hemispheres. They sorted electrode pairs by whether their direct corpus callosum connection had been disconnected or preserved using diffusion tensor imaging and native anatomical MRI, and they estimated functional connectivity between pairs of electrodes over homologous regions using phase-locking value. They found no significant differences in any frequency band between pairs of electrodes that had their corpus callosum connection disconnected and those that had an intact connection. The authors’ results may imply that the corpus callosum is not an obligatory mediator of connectivity between homologous sites in opposite hemispheres. This interhemispheric synchronization may also be linked to disruption of seizure activity.

scholarly journals On the role of the corpus callosum in interhemispheric functional connectivity in humans

2017 ◽  
Vol 114 (50) ◽  
pp. 13278-13283 ◽  
Author(s):  
Jarod L. Roland ◽  
Abraham Z. Snyder ◽  
Carl D. Hacker ◽  
Anish Mitra ◽  
Joshua S. Shimony ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Corpus Callosum ◽  
Parietal Lobe ◽  
Brain Regions ◽  
Resting State Functional Connectivity ◽  
Limited Sample ◽  
Temporal Correlations ◽  
Before And After

Resting state functional connectivity is defined in terms of temporal correlations between physiologic signals, most commonly studied using functional magnetic resonance imaging. Major features of functional connectivity correspond to structural (axonal) connectivity. However, this relation is not one-to-one. Interhemispheric functional connectivity in relation to the corpus callosum presents a case in point. Specifically, several reports have documented nearly intact interhemispheric functional connectivity in individuals in whom the corpus callosum (the major commissure between the hemispheres) never develops. To investigate this question, we assessed functional connectivity before and after surgical section of the corpus callosum in 22 patients with medically refractory epilepsy. Section of the corpus callosum markedly reduced interhemispheric functional connectivity. This effect was more profound in multimodal associative areas in the frontal and parietal lobe than primary regions of sensorimotor and visual function. Moreover, no evidence of recovery was observed in a limited sample in which multiyear, longitudinal follow-up was obtained. Comparison of partial vs. complete callosotomy revealed several effects implying the existence of polysynaptic functional connectivity between remote brain regions. Thus, our results demonstrate that callosal as well as extracallosal anatomical connections play a role in the maintenance of interhemispheric functional connectivity.

Resting-State Cortical Connectivity Underlying Cognitive-Motor Interactions in Gait and Postural Tasks in Young Adults

Neurology ◽  
2021 ◽  
Vol 98 (1 Supplement 1) ◽  
pp. S3.2-S3
Author(s):  
Nathan Morelli ◽  
Nathan Johnson ◽  
Kimberly Kaiser ◽  
Richard Andreatta ◽  
Nicholas Heebner ◽  
...  
Keyword(s):  
Young Adults ◽  
Functional Connectivity ◽  
Postural Control ◽  
Cognitive Performance ◽  
Dual Task ◽  
Resting State ◽  
Gait Speed ◽  
Network Connectivity ◽  
The Relationship

ObjectiveThe purpose of this study is to determine the relationship between intra- and internetwork connectivity and DTC of postural, gait, and cognitive performance in healthy, young adults.BackgroundDual-task (DT) deficits persist after return to activity in those recovering from a sports related concussion. However, little is known about the relationship of cortical network function to DT capacity. Current evidence regarding the relationship between network connectivity and dual-task balance and gait performance is limited by focusing on older adults and those with cognitive impairments, using a condensed set of task demands, and neglecting the role of connectivity in the ability to adapt to minimize DT cost (DTC).Design/MethodsTwelve adults (7 females; age: 23.41 ± 2.74 years; height: 1.73 ± 0.10 m; weight: 72.66 ± 11.25 kg) volunteered for this study. Participants completed resting-state functional magnetic resonance imaging, as well as single and DT variants of the Concussion Balance Test, Sensory Organization Test, and gait. Functional connectivity within and between the default mode (DMN), salience (SAL), and sensorimotor (SMN) networks were calculated for all subjects. Pearson's correlations were used to assess the association of connectivity to balance and gait speed DTC.ResultsInter-network connectivity between to DMN to the SAL and SMN demonstrated moderate to strong association to DTC of gait speed and postural control during tasks which perturbed sensory environments (r = −0.59 to 0.94, p < 0.05). There was no relationship between connectivity and DTC of cognitive performance during DT (r = −0.50 to 0.54, p > 0.05).ConclusionsOur findings highlight the role of the SAL, SMN, and DMN in cognitive-motor interactions during gait and postural control. Furthermore, functional connectivity underlying DT gait and static postural control performance express inverse relationships, suggesting task-dependent differences in system level processing.

Aberrant Thalamocortical Connectivity in Juvenile Myoclonic Epilepsy

2017 ◽  
Vol 28 (01) ◽  
pp. 1750034 ◽  
Author(s):  
S. Jiang ◽  
C. Luo ◽  
J. Gong ◽  
R. Peng ◽  
S. Ma ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Network Connectivity ◽  
Epileptic Activity ◽  
Juvenile Myoclonic Epilepsy ◽  
Myoclonic Epilepsy ◽  
Healthy Controls ◽  
Posterior Thalamus ◽  
Duration Of Disease ◽  
Subcortical Nuclei

The purpose of this study was to investigate the functional connectivity (FC) of thalamic subdivisions in patients with juvenile myoclonic epilepsy (JME). Resting state functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) data were acquired from 22 JME and 25 healthy controls. We first divided the thalamus into eight subdivisions by performing independent component analysis on tracking fibers and clustering thalamus-related FC maps. We then analyzed abnormal FC in each subdivision in JME compared with healthy controls, and we investigated their associations with clinical features. Eight thalamic sub-regions identified in the current study showed unbalanced thalamic FC in JME: decreased FC with the superior frontal gyrus and enhanced FC with the supplementary motor area in the posterior thalamus increased thalamic FC with the salience network (SN) and reduced FC with the default mode network (DMN). Abnormalities in thalamo-prefrontocortical networks might be related to the propagation of generalized spikes with frontocentral predominance in JME, and the network connectivity differences with the SN and DMN might be implicated in emotional and cognitive defects in JME. JME was also associated with enhanced FC among thalamic sub-regions and with the basal ganglia and cerebellum, suggesting the regulatory role of subcortical nuclei and the cerebellum on the thalamo-cortical circuit. Additionally, increased FC with the pallidum was positive related with the duration of disease. The present study provides emerging evidence of FC to understand that specific thalamic subdivisions contribute to the abnormalities of thalamic-cortical networks in JME. Moreover, the posterior thalamus could play a crucial role in generalized epileptic activity in JME.

Default network connectivity as a vulnerability marker for obsessive compulsive disorder

2013 ◽  
Vol 44 (7) ◽  
pp. 1475-1484 ◽  
Author(s):  
Z. W. Peng ◽  
T. Xu ◽  
Q. H. He ◽  
C. Z. Shi ◽  
Z. Wei ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Obsessive Compulsive Disorder ◽  
Genetic Risk ◽  
Temporal Cortex ◽  
Network Connectivity ◽  
Default Network ◽  
Healthy Controls ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Potential Marker

BackgroundAberrant functional connectivity within the default network is generally assumed to be involved in the pathophysiology of obsessive compulsive disorder (OCD); however, the genetic risk of default network connectivity in OCD remains largely unknown.MethodHere, we systematically investigated default network connectivity in 15 OCD patients, 15 paired unaffected siblings and 28 healthy controls. We sought to examine the profiles of default network connectivity in OCD patients and their siblings, exploring the correlation between abnormal default network connectivity and genetic risk for this population.ResultsCompared with healthy controls, OCD patients exhibited reduced strength of default network functional connectivity with the posterior cingulate cortex (PCC), and increased functional connectivity in the right inferior frontal lobe, insula, superior parietal cortex and superior temporal cortex, while their unaffected first-degree siblings only showed reduced local connectivity in the PCC.ConclusionsThese findings suggest that the disruptions of default network functional connectivity might be associated with family history of OCD. The decreased default network connectivity in both OCD patients and their unaffected siblings may serve as a potential marker of OCD.

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