On the Role of Bilateral Brain Hypofunction and Abnormal Lateralization of Cortical Information Flow as Neural Underpinnings of Conventional Metaphor Processing Impairment in Schizophrenia: An fMRI and EEG Study

AbstractFigurative language processing (e.g. metaphors) is commonly impaired in schizophrenia. In the present study, we investigated the neural activity and propagation of information within neural circuits related to the figurative speech, as a neural substrate of impaired conventional metaphor processing in schizophrenia. The study included 30 schizophrenia outpatients and 30 healthy controls, all of whom were assessed with a functional Magnetic Resonance Imaging (fMRI) and electroencephalography (EEG) punchline-based metaphor comprehension task including literal (neutral), figurative (metaphorical) and nonsense (absurd) endings. The blood oxygenation level-dependent signal was recorded with 3T MRI scanner and direction and strength of cortical information flow in the time course of task processing was estimated with a 64-channel EEG input for directed transfer function. The presented results revealed that the behavioral manifestation of impaired figurative language in schizophrenia is related to the hypofunction in the bilateral fronto-temporo-parietal brain regions (fMRI) and various differences in effective connectivity in the fronto-temporo-parietal circuit (EEG). Schizophrenia outpatients showed an abnormal pattern of connectivity during metaphor processing which was related to bilateral (but more pronounced at the left hemisphere) hypoactivation of the brain. Moreover, we found reversed lateralization patterns, i.e. a rightward-shifted pattern during metaphor processing in schizophrenia compared to the control group. In conclusion, the presented findings revealed that the impairment of the conventional metaphor processing in schizophrenia is related to the bilateral brain hypofunction, which supports the evidence on reversed lateralization of the language neural network and the existence of compensatory recruitment of alternative neural circuits in schizophrenia.

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Granger Causality of the Electroencephalogram Reveals Abrupt Global Loss of Cortical Information Flow during Propofol-induced Loss of Responsiveness

Anesthesiology ◽

10.1097/aln.0000000000003398 ◽

2020 ◽

Vol 133 (4) ◽

pp. 774-786 ◽

Cited By ~ 2

Author(s):

Rebecca M. Pullon ◽

Lucy Yan ◽

Jamie W. Sleigh ◽

Catherine E. Warnaby

Keyword(s):

Functional Connectivity ◽

Granger Causality ◽

Information Flow ◽

Behavioral Response ◽

Effective Connectivity ◽

Brain Regions ◽

Motor Tasks ◽

Loss Of Information ◽

Behavioral Responsiveness ◽

Scalp Electroencephalogram

Background It is a commonly held view that information flow between widely separated regions of the cerebral cortex is a necessary component in the generation of wakefulness (also termed “connected” consciousness). This study therefore hypothesized that loss of wakefulness caused by propofol anesthesia should be associated with loss of information flow, as estimated by the effective connectivity in the scalp electroencephalogram (EEG) signal. Methods Effective connectivity during anesthesia was quantified by applying bivariate Granger to multichannel EEG data recorded from 16 adult subjects undergoing a slow induction of, and emergence from, anesthesia with intravenous propofol. During wakefulness they were conducting various auditory and motor tasks. Functional connectivity using EEG coherence was also estimated. Results There was an abrupt, substantial, and global decrease in effective connectivity around the point of loss of responsiveness. Recovery of behavioral responsiveness was associated with a comparable recovery in information flow pattern (expressed as normalized values). The median (interquartile range) change was greatest in the delta frequency band: decreasing from 0.15 (0.21) 2 min before loss of behavioral response, to 0.06 (0.04) 2 min after loss of behavioral response (P < 0.001). Regional decreases in information flow were maximal in a posteromedial direction from lateral frontal and prefrontal regions (0.82 [0.24] 2 min before loss of responsiveness, decreasing to 0.17 [0.05] 2 min after), and least for information flow from posterior channels. The widespread decrease in bivariate Granger causality reflects loss of cortical coordination. The relationship between functional connectivity (coherence) and effective connectivity (Granger causality) was inconsistent. Conclusions Propofol-induced unresponsiveness is marked by a global decrease in information flow, greatest from the lateral frontal and prefrontal brain regions in a posterior and medial direction. Loss of information flow may be a useful measure of connected consciousness. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

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Altered Effective Connectivity during a Processing Speed Task in Individuals with Multiple Sclerosis

Journal of the International Neuropsychological Society ◽

10.1017/s1355617715001034 ◽

2016 ◽

Vol 22 (2) ◽

pp. 216-224 ◽

Cited By ~ 8

Author(s):

E. Dobryakova ◽

S.L. Costa ◽

G.R. Wylie ◽

J. DeLuca ◽

H.M. Genova

Keyword(s):

Multiple Sclerosis ◽

Processing Speed ◽

Effective Connectivity ◽

Brain Regions ◽

Brain Network ◽

Connectivity Pattern ◽

Control Group ◽

Dynamic Representation ◽

Speed Task ◽

Healthy Participants

AbstractObjectives: Processing speed impairment is the most prevalent cognitive deficit in individuals with multiple sclerosis (MS). However, the neural mechanisms associated with processing speed remain under debate. The current investigation provides a dynamic representation of the functioning of the brain network involved in processing speed by examining effective connectivity pattern during a processing speed task in healthy adults and in MS individuals with and without processing speed impairment. Methods: Group assignment (processing speed impaired vs. intact) was based on participants’ performance on the Symbol Digit Modalities test (Parmenter, Testa, Schretlen, Weinstock-Guttman, & Benedict, 2010). First, brain regions involved in the processing speed task were determined in healthy participants. Time series from these functional regions of interest of each group of participants were then subjected to the effective connectivity analysis (Independent Multiple-Sample Greedy Equivalence Search and Linear, Non-Gaussian Orientation, Fixed Structure algorithms) that showed causal influences of one region on another during task performance. Results: The connectivity pattern of the processing speed impaired group was significantly different from the connectivity pattern of the processing speed intact group and of the healthy control group. Differences in the strength of common connections were also observed. Conclusions: Effective connectivity results reveal that MS individuals with processing speed impairment not only have connections that differ from healthy participants and MS individuals without processing speed impairment, but also have increased strengths of connections. (JINS, 2016, 22, 216–224)

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Isn't It Ironic? An Electrophysiological Exploration of Figurative Language Processing

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2010.21411 ◽

2011 ◽

Vol 23 (2) ◽

pp. 277-293 ◽

Cited By ~ 84

Author(s):

Stefanie Regel ◽

Thomas C. Gunter ◽

Angela D. Friederici

Keyword(s):

Language Processing ◽

Cognitive Processes ◽

Time Course ◽

Figurative Language ◽

Semantic Integration ◽

Task Demands ◽

Brain Potentials ◽

Late Positivity ◽

Figurative Language Processing ◽

N400 Component

Although the neurocognitive processes underlying the comprehension of figurative language, especially metaphors and idioms, have been studied extensively, less is known about the processing of irony. In two experiments using event-related brain potentials (ERPs), we examined the types of cognitive processes involved in the comprehension of ironic and literal sentences and their relative time course. The experiments varied in modality (auditory, visual), task demands (comprehension task vs. passive reading), and probability of stimulus occurrence. ERPs consistently revealed a large late positivity (i.e., P600 component) in the absence of an N400 component for irony compared to equivalent literal sentences independent of modality. This P600 was shown to be unaffected by the factors task demands and probability of occurrence. Taken together, the findings suggest that the observed P600 is related to irony processing, and might be a reflection of pragmatic interpretation processes. During the comprehension of irony, no semantic integration difficulty arises (absence of N400), but late inferential processes appear to be necessary for understanding ironic meanings (presence of P600). This finding calls for a revision of current models of figurative language processing.

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Resting-state directed brain connectivity patterns in adolescents from source-reconstructed EEG signals based on information flow rate

10.1101/608299 ◽

2019 ◽

Cited By ~ 3

Author(s):

Dionissios Hristopulos ◽

Arif Babul ◽

Shazia Babul ◽

Leyla R Brucar ◽

Naznin Virji-Babul

Keyword(s):

Information Flow ◽

Flow Rate ◽

Resting State ◽

Brain Connectivity ◽

Effective Connectivity ◽

Brain Regions ◽

Brain Maturation ◽

Eeg Signals ◽

Stochastic Dynamical Systems ◽

Flow Rate Coefficient

Quantifying the brain's effective connectivity offers a unique window onto the causal architecture coupling the different regions of the brain. Here, we advocate a new, data-driven measure of directed (or effective) brain connectivity based on the recently developed information flow rate coefficient. The concept of the information flow rate is founded in the theory of stochastic dynamical systems and its derivation is based on first principles; unlike various commonly used linear and nonlinear correlations and empirical directional coefficients, the information flow rate can measure causal relations between time series with minimal assumptions. We apply the information flow rate to electroencephalography (EEG) signals in adolescent males to map out the directed, causal, spatial interactions between brain regions during resting-state conditions. To our knowledge, this is the first study of effective connectivity in the adolescent brain. Our analysis reveals that adolescents show a pattern of information flow that is strongly left lateralized, and consists of short and medium ranged bidirectional interactions across the frontal-central-temporal regions. These results suggest an intermediate state of brain maturation in adolescence.

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Developmental Increase in Top–Down and Bottom–Up Processing in a Phonological Task: An Effective Connectivity, fMRI Study

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2009.21065 ◽

2009 ◽

Vol 21 (6) ◽

pp. 1135-1145 ◽

Cited By ~ 48

Author(s):

Tali Bitan ◽

Jimmy Cheon ◽

Dong Lu ◽

Douglas D. Burman ◽

James R. Booth

Keyword(s):

Language Processing ◽

Effective Connectivity ◽

Inferior Frontal Gyrus ◽

Temporal Cortex ◽

Control Process ◽

Brain Regions ◽

Top Down ◽

Bottom Up ◽

Age Related ◽

Task Irrelevant

We examined age-related changes in the interactions among brain regions in children performing rhyming judgments on visually presented words. The difficulty of the task was manipulated by including a conflict between task-relevant (phonological) information and task-irrelevant (orthographic) information. The conflicting conditions included pairs of words that rhyme despite having different spelling patterns (jazz–has), or words that do not rhyme despite having similar spelling patterns (pint–mint). These were contrasted with nonconflicting pairs that have similar orthography and phonology (dime–lime) or different orthography and phonology (press–list). Using fMRI, we examined effective connectivity among five left hemisphere regions of interest: fusiform gyrus (FG), inferior frontal gyrus (IFG), intraparietal sulcus (IPS), lateral temporal cortex (LTC), and medial frontal gyrus (MeFG). Age-related increases were observed in the influence of the IFG and FG on the LTC, but only in conflicting conditions. These results reflect a developmental increase in the convergence of bottom–up and top–down information on the LTC. In older children, top–down control process may selectively enhance the sensitivity of the LTC to bottom–up information from the FG. This may be evident especially in situations that require selective enhancement of task-relevant versus task-irrelevant information. Altogether these results provide a direct evidence for a developmental increase in top–down control processes in language processing. The developmental increase in bottom–up processing may be secondary to the enhancement of top–down processes.

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Time Course of Evoked-potential Changes in Different Forms of Anomia in Aphasia

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2009.21117 ◽

2009 ◽

Vol 21 (8) ◽

pp. 1499-1510 ◽

Cited By ~ 32

Author(s):

Marina Laganaro ◽

Stéphanie Morand ◽

Armin Schnider

Keyword(s):

Picture Naming ◽

Time Course ◽

Time Windows ◽

Naming Task ◽

Brain Regions ◽

Word Production ◽

Event Related Potential ◽

Control Group ◽

Early Event ◽

Lexical Semantic

Impaired word production after brain damage can be due to impairment at lexical–semantic or at lexical–phonological levels of word encoding. These processes are thought to involve different brain regions and to have different time courses. The present study investigated the time course of electrophysiological correlates of anomia in 16 aphasic speakers, divided in two subgroups according to their anomic pattern (8 with lexical–semantic impairment and 8 with lexical–phonological impairment), in comparison to 16 healthy control subjects performing the same picture naming task. Differences in amplitudes and in topographic maps between groups were differently distributed when the whole heterogeneous group of aphasic patients was compared to the control group and when the two more homogeneous subgroups of anomic patients were analyzed. The entire aphasic group expressed different waveforms and topographic patterns than the control group starting about 100 msec after picture presentation. When two subgroups of aphasic patients are considered according to the underlying cognitive impairment, early event-related potential (ERP) abnormalities (100–250 msec) appeared only in the lexical–semantic subgroup, whereas later ERP abnormalities (300–450 msec) occurred only in the lexical–phonological subgroup. These results indicate that the time windows of ERP abnormalities vary depending on the underlying anomic impairment. Moreover, the findings give support to current hypotheses on the time course of processes involved in word production during picture naming.

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Analysis of Brain Functional Connectivity Neural Circuits in Children With Autism Based on Persistent Homology

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.745671 ◽

2021 ◽

Vol 15 ◽

Author(s):

Di Liang ◽

Shengxiang Xia ◽

Xianfu Zhang ◽

Weiwei Zhang

Keyword(s):

Functional Connectivity ◽

Neural Circuits ◽

Persistent Homology ◽

Brain Networks ◽

Brain Regions ◽

Autism Spectrum ◽

Unknown Etiology ◽

Control Group ◽

Threshold Values ◽

The Right

Autism spectrum disorder (ASD) is a complex neuropsychiatric disorder with a complex and unknown etiology. Statistics demonstrate that the number of people diagnosed with ASD is increasing in countries around the world. Currently, although many neuroimaging studies indicate that ASD is characterized by abnormal functional connectivity (FC) patterns within brain networks rather than local functional or structural abnormalities, the FC characteristics of ASD are still poorly understood. In this study, a Vietoris-Rips (VR) complex filtration model of the brain functional network was established by using resting-state functional magnetic resonance imaging (fMRI) data of children aged 6–13 years old [including 54 ASD patients and 52 typical development (TD) controls] from the Autism Brain Imaging Data Exchange (ABIDE) public database. VR complex filtration barcodes are calculated by using persistent homology to describe the changes in the FC neural circuits of brain networks. The number of FC neural circuits with different length ranges at different threshold values is calculated by using the barcodes, the different brain regions participating in FC neural circuits are discussed, and the connectivity characteristics of brain FC neural circuits in the two groups are compared and analyzed. Our results show that the number of FC neural circuits with lengths of 8–12 is significantly decreased in the ASD group compared with the TD control group at threshold values of 0.7, 0.8 and 0.9, and there is no significant difference in the number of FC neural circuits with lengths of 4–7 and 13–16 and lengths 16. When the thresholds are 0.7, 0.8, and 0.9, the number of FC neural circuits in some brain regions, such as the right orbital part of the superior frontal gyrus, the left supplementary motor area, the left hippocampus, and the right caudate nucleus, involved in the study is significantly decreased in the ASD group compared with the TD control group. The results of this study indicate that there are significant differences in the FC neural circuits of brain networks in the ASD group compared with the TD control group.

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Using arterial spin labelling to investigate spontaneous and evoked ongoing musculoskeletal pain

10.1101/163196 ◽

2017 ◽

Author(s):

Karolina A. Wartolowska ◽

Daniel P. Bulte ◽

Michael A. Chappell ◽

Mark Jenkinson ◽

Thomas W. Okell ◽

...

Keyword(s):

Musculoskeletal Pain ◽

Brain Regions ◽

Posterior Cingulate Cortex ◽

Blood Oxygenation ◽

Arterial Spin Labelling ◽

The Body ◽

Control Group ◽

Attractive Alternative ◽

Correlated Motion ◽

Spin Labelling

Clinical pain is difficult to study using standard Blood Oxygenation Level Dependent (BOLD) magnetic resonance imaging because it is often ongoing and, if evoked, it is associated with stimulus-correlated motion. Arterial spin labelling (ASL) offers an attractive alternative. This study used arm repositioning to evoke clinically-relevant musculoskeletal pain in patients with shoulder impingement syndrome. Fifty-five patients were scanned using a multi post-labelling delay pseudo-continuous ASL (pCASL) sequence, first with both arms along the body and then with the affected arm raised into a painful position. Twenty healthy volunteers were scanned as a control group. Arm repositioning resulted in increased perfusion in brain regions involved in sensory processing and movement integration, such as the contralateral primary motor and primary somatosensory cortex, mid- and posterior cingulate cortex, and, bilaterally, in the insular cortex/operculum, putamen, thalamus, midbrain and cerebellum. Perfusion in the thalamus, midbrain and cerebellum was larger in the patient group. Results of a post hoc analysis suggested that the observed perfusion changes were related to pain rather than arm repositioning. This study showed that ASL can be useful in research on clinical ongoing musculoskeletal pain but the technique is not sensitive enough to detect small differences in perfusion.

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Functionally distinct language and Theory of Mind networks are synchronized at rest and during language comprehension

Journal of Neurophysiology ◽

10.1152/jn.00619.2018 ◽

2019 ◽

Vol 121 (4) ◽

pp. 1244-1265 ◽

Cited By ~ 21

Author(s):

Alexander M. Paunov ◽

Idan A. Blank ◽

Evelina Fedorenko

Keyword(s):

Theory Of Mind ◽

Functional Mri ◽

Language Processing ◽

Language Comprehension ◽

Mental States ◽

Brain Regions ◽

Blood Oxygenation ◽

Social Reasoning ◽

Story Comprehension ◽

Dependent Signal

Communication requires the abilities to generate and interpret utterances and to infer the beliefs, desires, and goals of others (“Theory of Mind”; ToM). These two abilities have been shown to dissociate: individuals with aphasia retain the ability to think about others’ mental states; and individuals with autism are impaired in social reasoning, but their basic language processing is often intact. In line with this evidence from brain disorders, functional MRI (fMRI) studies have shown that linguistic and ToM abilities recruit distinct sets of brain regions. And yet, language is a social tool that allows us to share thoughts with one another. Thus, the language and ToM brain networks must share information despite being implemented in distinct neural circuits. Here, we investigated potential interactions between these networks during naturalistic cognition using functional correlations in fMRI. The networks were functionally defined in individual participants, in terms of preference for sentences over nonwords for language, and for belief inference over physical-event processing for ToM, with both a verbal and a nonverbal paradigm. Although, across experiments, interregion correlations within each network were higher than between-network correlations, we also observed above-baseline synchronization of blood oxygenation level-dependent signal fluctuations between the two networks during rest and story comprehension. This synchronization was functionally specific: neither network was synchronized with the executive control network (functionally defined in terms of preference for a harder over easier version of an executive task). Thus, coordination between the language and ToM networks appears to be an inherent and specific characteristic of their functional architecture.NEW & NOTEWORTHY Humans differ from nonhuman primates in their abilities to communicate linguistically and to infer others’ mental states. Although linguistic and social abilities appear to be interlinked onto- and phylogenetically, they are dissociated in the adult human brain. Yet successful communication requires language and social reasoning to work in concert. Using functional MRI, we show that language regions are synchronized with social regions during rest and language comprehension, pointing to a possible mechanism for internetwork interaction.

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067 Causal Communication Across the Electrode Manifold During Slow Oscillations

SLEEP ◽

10.1093/sleep/zsab072.066 ◽

2021 ◽

Vol 44 (Supplement_2) ◽

pp. A28-A28

Author(s):

Hamid Niknazar ◽

Paola Malerba ◽

Sara Mednick

Keyword(s):

Information Flow ◽

Effective Connectivity ◽

Source Region ◽

Brain Networks ◽

Brain Regions ◽

Sleep Stages ◽

P Value ◽

Mixed Effect ◽

Causal Information ◽

Source And Sink

Abstract Introduction The slow oscillation (0.5-1Hz, SO) is the most studied sleep waveform and reflects sleep homeostasis and is crucial for memory consolidation. It is not clear how SO causally affects brain networks. We used the effective connectivity technique to investigate causal information flow across the electrode manifold during the SO. Methods Night sleep EEG signals of 59 adult participants were recorded and visually scored into five sleep stages. We used three EEG channels for each region including frontal, central, parietal, and occipital. SOs were detected automatically and signals from one second before to one second after the SO’s troughs were used for estimating effective connectivity in SO and non-SO windows. Windowing technique and generalized partial directed coherence were employed to estimate causal information flow (CIF) between selected brain regions. The Linear mixed-effect (LME) method was used to model the peaks of the CIF based on different predictors including SO channel, source and sink of CIF, and distance between each of SO channel, source and sink regions. Results The results of CIF estimation showed two peaks of CIF about 250ms before and after the SO’s trough, but no difference between CIF in SO’s trough and non-SO windows. We found no effect of source and sink regions, and their distance on CIF (p-value > 0.05). However, distance between SO channel to source and sink region (p-value < 0.05) significantly predicted CIF. The coefficients of the LME model showed a direct effect of distance between SO channel to sink region and opposite effect of distance between SO channel to source region on CIF peaks. Conclusion The results showed there were significant changes of brain regions causal communication during SOs and these changes were affected by the distance of SO channel to sink and source region of CIF. Channels that are closer to the SO send more information and regions farther from the SO channel receive more information. Based on the results, we hypothesize that the SO brain networks are optimized to facilitate communication between regions that are far apart. Support (if any):

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