scholarly journals Consciousness and the Dimensionality of DOC Patients via the Generalized Ising Model

2020 ◽  
Vol 9 (5) ◽  
pp. 1342 ◽  
Author(s):  
Pubuditha M. Abeyasinghe ◽  
Marco Aiello ◽  
Emily S. Nichols ◽  
Carlo Cavaliere ◽  
Salvatore Fiorenza ◽  
...  
Keyword(s):  
Ising Model ◽  
Computational Modeling ◽  
Information Transfer ◽  
Brain Injuries ◽  
Structural Connectivity ◽  
Complex Data ◽  
Healthy Controls ◽  
Brain Functions ◽  
States Of Consciousness ◽  
Generalized Ising Model

The data from patients with severe brain injuries show complex brain functions. Due to the difficulties associated with these complex data, computational modeling is an especially useful tool to examine the structure–function relationship in these populations. By using computational modeling for patients with a disorder of consciousness (DoC), not only we can understand the changes of information transfer, but we also can test changes to different states of consciousness by hypothetically changing the anatomical structure. The generalized Ising model (GIM), which specializes in using structural connectivity to simulate functional connectivity, has been proven to effectively capture the relationship between anatomical structures and the spontaneous fluctuations of healthy controls (HCs). In the present study we implemented the GIM in 25 HCs as well as in 13 DoC patients diagnosed at three different states of consciousness. Simulated data were analyzed and the criticality and dimensionality were calculated for both groups; together, those values capture the level of information transfer in the brain. Ratifying previous studies, criticality was observed in simulations of HCs. We were also able to observe criticality for DoC patients, concluding that the GIM is generalizable for DoC patients. Furthermore, dimensionality increased for the DoC group as compared to healthy controls, and could distinguish different diagnostic groups of DoC patients.

scholarly journals Loss of consciousness reduces the stability of brain hubs and the heterogeneity of brain dynamics

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ane López-González ◽  
Rajanikant Panda ◽  
Adrián Ponce-Alvarez ◽  
Gorka Zamora-López ◽  
Anira Escrichs ◽  
...  
Keyword(s):  
Brain Injuries ◽  
Brain Activity ◽  
Structural Connectivity ◽  
Conscious State ◽  
Brain Dynamics ◽  
Disorder Of Consciousness ◽  
Low Level ◽  
States Of Consciousness ◽  
The Stability ◽  
Different Levels

AbstractLow-level states of consciousness are characterized by disruptions of brain activity that sustain arousal and awareness. Yet, how structural, dynamical, local and network brain properties interplay in the different levels of consciousness is unknown. Here, we study fMRI brain dynamics from patients that suffered brain injuries leading to a disorder of consciousness and from healthy subjects undergoing propofol-induced sedation. We show that pathological and pharmacological low-level states of consciousness display less recurrent, less connected and more segregated synchronization patterns than conscious state. We use whole-brain models built upon healthy and injured structural connectivity to interpret these dynamical effects. We found that low-level states of consciousness were associated with reduced network interactions, together with more homogeneous and more structurally constrained local dynamics. Notably, these changes lead the structural hub regions to lose their stability during low-level states of consciousness, thus attenuating the differences between hubs and non-hubs brain dynamics.

scholarly journals Modeling an auditory stimulated brain under altered states of consciousness using the generalized Ising model

NeuroImage ◽  
2020 ◽  
Vol 223 ◽  
pp. 117367 ◽  
Author(s):  
Sivayini Kandeepan ◽  
Jorge Rudas ◽  
Francisco Gomez ◽  
Bobby Stojanoski ◽  
Sreeram Valluri ◽  
...  
Keyword(s):  
Ising Model ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
States Of Consciousness ◽  
Generalized Ising Model

scholarly journals Miswiring of Frontostriatal Projections in Schizophrenia

2020 ◽  
Vol 46 (4) ◽  
pp. 990-998 ◽  
Author(s):  
James J Levitt ◽  
Paul G Nestor ◽  
Marek Kubicki ◽  
Amanda E Lyall ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Diffusion Magnetic Resonance Imaging ◽  
Right Hemisphere ◽  
Structural Connectivity ◽  
Chronic Schizophrenia ◽  
Input Pattern ◽  
Healthy Controls ◽  
Resonance Imaging ◽  
Circuit Integration ◽  
Projection Zone

Abstract We investigated brain wiring in chronic schizophrenia and healthy controls in frontostriatal circuits using diffusion magnetic resonance imaging tractography in a novel way. We extracted diffusion streamlines in 27 chronic schizophrenia and 26 healthy controls connecting 4 frontal subregions to the striatum. We labeled the projection zone striatal surface voxels into 2 subtypes: dominant-input from a single cortical subregion, and, functionally integrative, with mixed-input from diverse cortical subregions. We showed: 1) a group difference for total striatal surface voxel number (P = .045) driven by fewer mixed-input voxels in the left (P  = .007), but not right, hemisphere; 2) a group by hemisphere interaction for the ratio quotient between voxel subtypes (P  = .04) with a left (P  = .006), but not right, hemisphere increase in schizophrenia, also reflecting fewer mixed-input voxels; and 3) fewer mixed-input voxel counts in schizophrenia (P  = .045) driven by differences in left hemisphere limbic (P  = .007) and associative (P  = .01), but not sensorimotor, striatum. These results demonstrate a less integrative pattern of frontostriatal structural connectivity in chronic schizophrenia. A diminished integrative pattern yields a less complex input pattern to the striatum from the cortex with less circuit integration at the level of the striatum. Further, as brain wiring occurs during early development, aberrant brain wiring could serve as a developmental biomarker for schizophrenia.

scholarly journals Abnormalities of EEG Microstates In Drug-Naïve, First-Episode Schizophrenia

2021 ◽  
Author(s):  
Qiaoling Sun ◽  
Linlin Zhao ◽  
Liwen Tan
Keyword(s):  
Clinical Symptoms ◽  
Early Stage ◽  
First Episode ◽  
Healthy Controls ◽  
Brain Functions ◽  
Class D ◽  
Syndrome Scale ◽  
Drug Naïve ◽  
Microstate Analysis ◽  
First Episode Schizophrenia

Abstract Objective: Microstate analysis is a powerful tool to probe the brain functions, and changes in microstates under electroencephalography (EEG) have been repeatedly reported in patients with schizophrenia. This study aimed to investigate the dynamics of EEG microstates in drug-naïve, first-episode schizophrenia (FE-SCH) and to test the relationship between EEG microstates and clinical symptoms.Methods: Resting-state EEG were recorded for 23 patients with FE-SCH and 23 healthy controls using a 64-channel cap. Three parameters, i.e., contribution, duration, and occurrence, of the four microstate classes were calculated. Group differences in EEG microstates and their clinical symptoms (assessed using the Positive and Negative Syndrome Scale) were analyzed.Results: Compared with healthy controls, patients with FE-SCH showed increased duration, occurrence and contribution of microstate class C and decreased contribution and occurrence of microstate class D. In addition, the score of positive symptoms in PANSS was negatively correlated with the occurrence of microstate D.Conclusions: Our findings showed abnormal patterns of EEG microstates in drug-naïve, first-episode schizophrenia, which might help distinguish individuals with schizophrenia in the early stage and develop early intervention strategies.

The Influence of Cortico-Cerebellar Structural Connectivity on Cortical Excitability in Chronic Stroke

2019 ◽  
Vol 30 (3) ◽  
pp. 1330-1344
Author(s):  
Stephanie Guder ◽  
Benedikt M Frey ◽  
Winifried Backhaus ◽  
Hanna Braass ◽  
Jan E Timmermann ◽  
...  
Keyword(s):  
Primary Motor Cortex ◽  
Structural Integrity ◽  
Cortical Excitability ◽  
Structural Information ◽  
Motor Evoked Potentials ◽  
Structural Connectivity ◽  
Chronic Stroke ◽  
Motor Output ◽  
Healthy Controls ◽  
Stroke Patients

Abstract Brain imaging has recently evidenced that the structural state of distinct reciprocal cortico-cerebellar fiber tracts, the dentato-thalamo-cortical tract (DTCT), and the cortico-ponto-cerebellar tract (CPCeT), significantly influences residual motor output in chronic stroke patients, independent from the level of damage to the corticospinal tract (CST). Whether such structural information might also directly relate to measures of cortical excitability is an open question. Eighteen chronic stroke patients with supratentorial ischemic lesions and 17 healthy controls underwent transcranial magnetic stimulation to assess recruitment curves of motor evoked potentials of both hemispheres. Diffusion-weighted imaging and probabilistic tractography were applied to reconstruct reciprocal cortico-cerebellar motor tracts between the primary motor cortex and the cerebellum. Tract-related microstructure was estimated by means of fractional anisotropy, and linear regression modeling was used to relate it to cortical excitability. The main finding was a significant association between cortical excitability and the structural integrity of the DTCT, the main cerebellar outflow tract, independent from the level of damage to the CST. A comparable relationship was neither detectable for the CPCeT nor for the healthy controls. This finding contributes to a mechanistic understanding of the putative supportive role of the cerebellum for residual motor output by facilitating cortical excitability after stroke.

High-temperature approach to the generalized Ising model

1982 ◽  
Vol 25 (9) ◽  
pp. 5875-5881 ◽  
Author(s):  
J. Naudts ◽  
S. D. Mahant
Keyword(s):  
High Temperature ◽  
Ising Model ◽  
Generalized Ising Model

scholarly journals A diffusion tensor imaging study of structural dysconnectivity in never-medicated, first-episode schizophrenia

2007 ◽  
Vol 38 (6) ◽  
pp. 877-885 ◽  
Author(s):  
V. Cheung ◽  
C. Cheung ◽  
G. M. McAlonan ◽  
Y. Deng ◽  
J. G. Wong ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Corpus Callosum ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
First Episode ◽  
Cerebral Peduncle ◽  
Healthy Controls ◽  
Subcortical Region ◽  
First Episode Schizophrenia

BackgroundDiffusion tensor imaging (DTI) can be used to investigate cerebral structural connectivity in never-medicated individuals with first-episode schizophrenia.MethodSubjects with first-episode schizophrenia according to DSM-IV-R who had never been exposed to antipsychotic medication (n=25) and healthy controls (n=26) were recruited. Groups were matched for age, gender, best parental socio-economic status and ethnicity. All subjects underwent DTI and structural magnetic resonance imaging (MRI) scans. Voxel-based analysis was performed to investigate brain regions where fractional anisotropy (FA) values differed significantly between groups. A confirmatory region-of-interest (ROI) analysis of FA scores was performed in which regions were placed blind to group membership.ResultsIn patients, FA values significantly lower than those in healthy controls were located in the left fronto-occipital fasciculus, left inferior longitudinal fasciculus, white matter adjacent to right precuneus, splenium of corpus callosum, right posterior limb of internal capsule, white matter adjacent to right substantia nigra, and left cerebral peduncle. ROI analysis of the corpus callosum confirmed that the patient group had significantly lower mean FA values than the controls in the splenium but not in the genu. The intra-class correlation coefficient (ICC) for independent ROI measurements was 0.90 (genu) and 0.90 (splenium). There were no regions where FA values were significantly higher in the patients than in the healthy controls.ConclusionsWidespread structural dysconnectivity, including the subcortical region, is already present in neuroleptic-naive patients in their first episode of illness.

scholarly journals Management of Traumatic Brain Injuries with Brain Concussion – A Review

2021 ◽  
pp. 249-253
Author(s):  
Hisham Mohammed Sonbul ◽  
Abdulsamad Yahya Ahmadi ◽  
Ahmed Mohammed Al Hammad ◽  
Aqeelah Adel Alhabeeb ◽  
Mohammed Ahmedabed I. Abualsaoud ◽  
...  
Keyword(s):  
Brain Injuries ◽  
Hospital Admissions ◽  
Traumatic Brain Injuries ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Emergency Rooms ◽  
Brain Concussion ◽  
Concussion Management ◽  
States Of Consciousness ◽  
Severity Of Injury

A typical occurrence in emergency rooms is traumatic brain injury (TBI) resulting from head trauma which is normally responsible for far more than 1 million visits per year. The magnitude of TBIs varies from mild, intermittent symptoms to longer periods of altered states of consciousness. The precise mechanism of concussion is indefinite. In serious brain trauma, Axon tearing is expected, but there is no evidence for this concussion process. Most concussion patients improve rapidly and entirely. Concussion management is usually supportive and some cases may need hospital admissions and ICU care according to severity of injury and related symptoms.

scholarly journals A Connectome-Based Approach to Assess Motor Outcome after Neonatal Arterial Ischemic Stroke

2020 ◽  
Author(s):  
Mariam Al Harrach ◽  
Pablo Pretzel ◽  
Samuel Groeschel ◽  
François Rousseau ◽  
Thijs Dhollander ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Structural Changes ◽  
Structural Connectivity ◽  
Multiple Linear Regression Model ◽  
Brain Regions ◽  
Motor Deficit ◽  
Healthy Controls ◽  
Arterial Ischemic Stroke ◽  
Motor Outcome ◽  
Motor Areas

AbstractObjectivestudies of motor outcome after Neonatal Arterial Ischemic Stroke (NAIS) often rely on lesion mapping using MRI. However, clinical measurements indicate that motor deficit can be different than what would solely be anticipated by the lesion extent and location. Because this may be explained by the cortical disconnections between motor areas due to necrosis following the stroke, the investigation of the motor network can help in the understanding of visual inspection and outcome discrepancy. In this study, we propose to examine the structural connectivity between motor areas in NAIS patients compared to healthy controls in order to define the cortical and subcortical connections that can reflect the motor outcomeMethods30 healthy controls and 32 NAIS patients with and without Cerebral Palsy (CP) underwent MRI acquisition and manual assessment. The connectome of all participants was obtained from T1-weighted and diffusion-weighted imaging.Resultssignificant disconnections in the lesioned and contra-lesioned hemispheres of patients were found. Furthermore, significant correlations were detected between the structural connectivity metric of specific motor areas and manuality assessed by the Box and Block Test (BBT) scores in patients.Interpretationusing the connectivity measures of these links the BBT score can be estimated using a multiple linear regression model. In addition, the presence or not of CP can also be predicted using the KNN classification algorithm. According to our results, the structural connectome can be an asset in the estimation of gross manual dexterity and can help uncover structural changes between brain regions related to NAIS.

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