scholarly journals Increased heterogeneity and task-related reconfiguration of functional connectivity within a lexicosemantic network in autism

2021 ◽  
Author(s):  
Apeksha Sridhar ◽  
R. Joanna Jao Keehn ◽  
Molly K Wilkinson ◽  
Yangfeifei Gao ◽  
Michael Olson ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Network Architecture ◽  
High Performance ◽  
Lexical Processing ◽  
Interindividual Variability ◽  
Pulse Sequences ◽  
Autism Spectrum ◽  
Decision Task ◽  
Regional Patterns ◽  
And Task

Autism spectrum disorder (ASD) is highly heterogeneous in etiology and clinical presentation. Findings on intrinsic functional connectivity (FC) or task-induced FC in ASD have been inconsistent including both over- and underconnectivity and diverse regional patterns. As FC patterns change across different cognitive demands, a novel and more comprehensive approach to network architecture in ASD is to examine the change in FC patterns between rest and task states, referred to as reconfiguration. This approach is suitable for investigating inefficient network connectivity that may underlie impaired behavioral functioning in clinical disorders. We used functional magnetic resonance imaging (fMRI) to examine FC reconfiguration during lexical processing, which is often affected in ASD, with additional focus on interindividual variability. Thirty adolescents with ASD and a matched group of 23 typically developing (TD) participants completed a lexicosemantic decision task during fMRI, using multiecho-multiband pulse sequences with advanced BOLD signal sensitivity and artifact removal. Regions of interest (ROIs) were selected based on task-related activation across both groups, and FC and reconfiguration were compared between groups. The ASD group showed increased interindividual variability and overall greater reconfiguration than the TD group. An ASD subgroup with typical performance accuracy (at the level of TD participants) showed reduced similarity and typicality of FC during the task. In this ASD subgroup, greater FC reconfiguration was associated with increased language skills. Findings suggest that intrinsic functional networks in ASD may be inefficiently organized for lexicosemantic decisions and may require greater reconfiguration during task processing, with high performance levels in some individuals being achieved through idiosyncratic mechanisms.

Principal States of Dynamic Functional Connectivity Reveal the Link Between Resting-State and Task-State Brain: An fMRI Study

2018 ◽  
Vol 28 (07) ◽  
pp. 1850002 ◽  
Author(s):  
Lin Cheng ◽  
Yang Zhu ◽  
Junfeng Sun ◽  
Lifu Deng ◽  
Naying He ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Spatial Patterns ◽  
Resting State ◽  
Network Architecture ◽  
Brain Networks ◽  
Temporal Patterns ◽  
Blood Oxygenation ◽  
Default Mode ◽  
The Brain ◽  
And Task

Task-related reorganization of functional connectivity (FC) has been widely investigated. Under classic static FC analysis, brain networks under task and rest have been demonstrated a general similarity. However, brain activity and cognitive process are believed to be dynamic and adaptive. Since static FC inherently ignores the distinct temporal patterns between rest and task, dynamic FC may be more a suitable technique to characterize the brain’s dynamic and adaptive activities. In this study, we adopted [Formula: see text]-means clustering to investigate task-related spatiotemporal reorganization of dynamic brain networks and hypothesized that dynamic FC would be able to reveal the link between resting-state and task-state brain organization, including broadly similar spatial patterns but distinct temporal patterns. In order to test this hypothesis, this study examined the dynamic FC in default-mode network (DMN) and motor-related network (MN) using Blood-Oxygenation-Level-Dependent (BOLD)-fMRI data from 26 healthy subjects during rest (REST) and a hand closing-and-opening (HCO) task. Two principal FC states in REST and one principal FC state in HCO were identified. The first principal FC state in REST was found similar to that in HCO, which appeared to represent intrinsic network architecture and validated the broadly similar spatial patterns between REST and HCO. However, the second FC principal state in REST with much shorter “dwell time” implied the transient functional relationship between DMN and MN during REST. In addition, a more frequent shifting between two principal FC states indicated that brain network dynamically maintained a “default mode” in the motor system during REST, whereas the presence of a single principal FC state and reduced FC variability implied a more temporally stable connectivity during HCO, validating the distinct temporal patterns between REST and HCO. Our results further demonstrated that dynamic FC analysis could offer unique insights in understanding how the brain reorganizes itself during rest and task states, and the ways in which the brain adaptively responds to the cognitive requirements of tasks.

Influence of Primary Auditory Cortex in the Characterization of Autism Spectrum in Young Adults using Brain Connectivity Parameters and Deep Belief Networks: An fMRI Study

2020 ◽  
Vol 16 (9) ◽  
pp. 1059-1073
Author(s):  
Vidhusha Srinivasan ◽  
N. Udayakumar ◽  
Kavitha Anandan
Keyword(s):  
Functional Connectivity ◽  
Auditory Cortex ◽  
Language Processing ◽  
Brain Connectivity ◽  
Primary Auditory Cortex ◽  
Autism Spectrum ◽  
Belief Networks ◽  
Deep Belief Networks ◽  
High Functioning ◽  
Low Functioning

Background: The spectrum of autism encompasses High Functioning Autism (HFA) and Low Functioning Autism (LFA). Brain mapping studies have revealed that autism individuals have overlaps in brain behavioural characteristics. Generally, high functioning individuals are known to exhibit higher intelligence and better language processing abilities. However, specific mechanisms associated with their functional capabilities are still under research. Objective: This work addresses the overlapping phenomenon present in autism spectrum through functional connectivity patterns along with brain connectivity parameters and distinguishes the classes using deep belief networks. Methods: The task-based functional Magnetic Resonance Images (fMRI) of both high and low functioning autistic groups were acquired from ABIDE database, for 58 low functioning against 43 high functioning individuals while they were involved in a defined language processing task. The language processing regions of the brain, along with Default Mode Network (DMN) have been considered for the analysis. The functional connectivity maps have been plotted through graph theory procedures. Brain connectivity parameters such as Granger Causality (GC) and Phase Slope Index (PSI) have been calculated for the individual groups. These parameters have been fed to Deep Belief Networks (DBN) to classify the subjects under consideration as either LFA or HFA. Results: Results showed increased functional connectivity in high functioning subjects. It was found that the additional interaction of the Primary Auditory Cortex lying in the temporal lobe, with other regions of interest complimented their enhanced connectivity. Results were validated using DBN measuring the classification accuracy of 85.85% for high functioning and 81.71% for the low functioning group. Conclusion: Since it is known that autism involves enhanced, but imbalanced components of intelligence, the reason behind the supremacy of high functioning group in language processing and region responsible for enhanced connectivity has been recognized. Therefore, this work that suggests the effect of Primary Auditory Cortex in characterizing the dominance of language processing in high functioning young adults seems to be highly significant in discriminating different groups in autism spectrum.

scholarly journals Structural and functional brain-wide alterations in A350V Iqsec2 mutant mice displaying autistic-like behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniela Lichtman ◽  
Eyal Bergmann ◽  
Alexandra Kavushansky ◽  
Nadav Cohen ◽  
Nina S. Levy ◽  
...  
Keyword(s):  
Social Behavior ◽  
Functional Connectivity ◽  
Mouse Model ◽  
Ampa Receptor ◽  
Social Preference ◽  
Autism Spectrum ◽  
Receptor Trafficking ◽  
Anterior Cingulate ◽  
The Impact ◽  
Ampa Receptor Trafficking

AbstractIQSEC2 is an X-linked gene that is associated with autism spectrum disorder (ASD), intellectual disability, and epilepsy. IQSEC2 is a postsynaptic density protein, localized on excitatory synapses as part of the NMDA receptor complex and is suggested to play a role in AMPA receptor trafficking and mediation of long-term depression. Here, we present brain-wide structural volumetric and functional connectivity characterization in a novel mouse model with a missense mutation in the IQ domain of IQSEC2 (A350V). Using high-resolution structural and functional MRI, we show that animals with the A350V mutation display increased whole-brain volume which was further found to be specific to the cerebral cortex and hippocampus. Moreover, using a data-driven approach we identify putative alterations in structure–function relations of the frontal, auditory, and visual networks in A350V mice. Examination of these alterations revealed an increase in functional connectivity between the anterior cingulate cortex and the dorsomedial striatum. We also show that corticostriatal functional connectivity is correlated with individual variability in social behavior only in A350V mice, as assessed using the three-chamber social preference test. Our results at the systems-level bridge the impact of previously reported changes in AMPA receptor trafficking to network-level disruption and impaired social behavior. Further, the A350V mouse model recapitulates similarly reported brain-wide changes in other ASD mouse models, with substantially different cellular-level pathologies that nonetheless result in similar brain-wide alterations, suggesting that novel therapeutic approaches in ASD that result in systems-level rescue will be relevant to IQSEC2 mutations.

Nickel sulfide nanoworm network architecture as a binder-free high-performance non-enzymatic glucose sensor

2021 ◽  
Vol 188 (2) ◽  
Author(s):  
Alan Meng ◽  
Xiaocheng Hong ◽  
Haiqin Zhang ◽  
Wenli Tian ◽  
Zhenjiang Li ◽  
...  
Keyword(s):  
Network Architecture ◽  
High Performance ◽  
Nickel Sulfide ◽  
Glucose Sensor ◽  
Binder Free

scholarly journals Effective ion pathways and 3D conductive carbon networks in bentonite host enable stable and high-rate lithium–sulfur batteries

2021 ◽  
Vol 10 (1) ◽  
pp. 20-33
Author(s):  
Lian Wu ◽  
Yongqiang Dai ◽  
Wei Zeng ◽  
Jintao Huang ◽  
Bing Liao ◽  
...  
Keyword(s):  
Network Architecture ◽  
High Performance ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
High Rate ◽  
Lithium Sulfur Batteries ◽  
Carbon Networks ◽  
Carbon Coated ◽  
Lithium Sulfur ◽  
Initial Capacity

Abstract Fast charge transfer and lithium-ion transport in the electrodes are necessary for high performance Li–S batteries. Herein, a N-doped carbon-coated intercalated-bentonite (Bent@C) with interlamellar ion path and 3D conductive network architecture is designed to improve the performance of Li–S batteries by expediting ion/electron transport in the cathode. The interlamellar ion pathways are constructed through inorganic/organic intercalation of bentonite. The 3D conductive networks consist of N-doped carbon, both in the interlayer and on the surface of the modified bentonite. Benefiting from the unique structure of the Bent@C, the S/Bent@C cathode exhibits a high initial capacity of 1,361 mA h g−1 at 0.2C and achieves a high reversible capacity of 618.1 m Ah g−1 at 2C after 500 cycles with a sulfur loading of 2 mg cm−2. Moreover, with a higher sulfur loading of 3.0 mg cm−2, the cathode still delivers a reversible capacity of 560.2 mA h g−1 at 0.1C after 100 cycles.

Lateralization of lexical processing in monolinguals and bilinguals

2021 ◽  
pp. 136700692110188
Author(s):  
Filiz Mergen ◽  
Gulmira Kuruoglu
Keyword(s):  
Lexical Processing ◽  
Response Times ◽  
Visual Fields ◽  
Decision Task ◽  
Bilingual Speakers ◽  
Visual Hemifield ◽  
Significant Difference ◽  
Brain Correlates ◽  
Orthographic Neighbors

Aims and objectives: This study aims to investigate how lexical processing (LP) is organized in early Turkish–English bilinguals and Turkish monolinguals. Methodology: We used a visual hemifield paradigm where bilingual ( n = 48) and monolingual ( n = 53) participants performed a lexical decision task. Bilingual participants performed the task in both their languages. Data and analysis: We recorded response times (RTs) and the accuracy rates (ARs) of the participants. An analysis of variance and t-test were run to analyze the bilingual and monolingual data, respectively. Findings: The results obtained from the analysis of the RTs and ARs for the Turkish and English words showed a balanced hemispheric organization in LP in bilingual speakers. The RTs for Turkish words in the monolingual group provided supportive evidence for the predominant role of the left hemisphere in LP. However, no significant difference was found in the accuracy of their answers, suggesting that the monolingual participants’ performance was not influenced by visual field of presentation of the words. Finally, the comparison of the two groups revealed that bilingual participants’ performance was inferior to monolinguals’ in speed and accuracy of processing of words presented in both visual fields. This result gives further support for the differential representation of LP in monolinguals and bilinguals. Originality: The psycholinguistic literature abounds with studies of LP in bilinguals and monolinguals from a variety of language backgrounds; however, there is much less data regarding the brain correlates of LP in Turkish–English bilinguals and Turkish monolinguals. Implications: Since Turkish–English bilinguals and Turkish monolinguals are underrepresented in the literature as compared to the population who speak other languages with alphabetic writing, this study provides preliminary data for future studies. Limitations: We did not control for gender or lexical factors such as orthographic neighbors when designing the word sets used as stimuli.

scholarly journals Increased Functional Connectivity Between Subcortical and Cortical Resting-State Networks in Autism Spectrum Disorder

2015 ◽  
Vol 72 (8) ◽  
pp. 767 ◽  
Author(s):  
Leonardo Cerliani ◽  
Maarten Mennes ◽  
Rajat M. Thomas ◽  
Adriana Di Martino ◽  
Marc Thioux ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Functional Connectivity ◽  
Resting State ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Resting State Networks
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