scholarly journals Effective connectivity inferred from fMRI transition dynamics during movie viewing points to a balanced reconfiguration of cortical interactions

2017 ◽  
Author(s):  
Matthieu Gilson ◽  
Gustavo Deco ◽  
Karl Friston ◽  
Patric Hagmann ◽  
Dante Mantini ◽  
...  
Keyword(s):  
Effective Connectivity ◽  
Functional Integration ◽  
Brain Regions ◽  
Connectivity Pattern ◽  
Model Parameters ◽  
Auditory Information ◽  
Brain Areas ◽  
Brain Hemispheres ◽  
Dynamic Coordination ◽  
The Brain

AbstractOur behavior entails a flexible and context-sensitive interplay between brain areas to integrate information according to goal-directed requirements. How-ever, the neural mechanisms governing the entrainment of functionally specialized brain areas remain poorly understood. In particular, the question arises whether observed changes in the regional activity for different cognitive conditions are explained by modifications of the inputs to the brain or its connectivity? We observe that transitions of fMRI activity between areas convey information about the tasks performed by 19 subjects, watching a movie versus a black screen (rest). We use a model-based framework that explains this spatiotemporal functional connectivity pattern by the local variability for 66 cortical regions and the network effective connectivity between them. We find that, among the estimated model parameters, movie viewing affects to a larger extent the local activity, which we interpret as extrinsic changes related to the increased stimulus load. However, detailed changes in the effective connectivity preserve a balance in the propagating activity and select specific pathways such that high-level brain regions integrate visual and auditory information, in particular boosting the communication between the two brain hemispheres. These findings speak to a dynamic coordination underlying the functional integration in the brain.

Differential recovery of acetylcholinesterase in guinea pig muscle and brain regions after soman treatment

1998 ◽  
Vol 17 (3) ◽  
pp. 157-162 ◽  
Author(s):  
Maxine C Lintern ◽  
Janet R Wetherell ◽  
Margaret E Smith
Keyword(s):  
Enzyme Activity ◽  
Time Course ◽  
Brain Regions ◽  
Similar Rate ◽  
Molecular Forms ◽  
Similar Degree ◽  
Brain Areas ◽  
Pig Muscle ◽  
Rate Of Recovery ◽  
The Brain

1 In brain areas of untreated guinea-pigs the highest activity of acetylcholinesterase was seen in the striatum and cerebellum, followed by the midbrain, medulla-pons and cortex, and the lowest in the hippocampus. The activity in diaphragm was sevenfold lower than in the hippocampus. 2 At 1 h after soman (27 mg/kg) administration the activity of the enzyme was dramatically reduced in all tissues studied. In muscle the three major molecular forms (A12, G4 and G1) showed a similar degree of inhibition and a similar rate of recovery and the activity had returned to normal by 7 days. 3 In the brain soman inhibited the G4 form more than the G1 form. The hippocampus, cortex and midbrain showed the greatest reductions in enzyme activity. At 7 days the activity in the cortex, medulla pons and striatum had recovered but in the hippocampus, midbrain and cerebellum it was still inhibited. 4 Thus the effects of soman administration varied in severity and time course in the different tissues studied. However the enzyme activity was still reduced in all tissues at 24 h when the overt signs of poisoning had disappeared.

scholarly journals Recent developments in cognitive fMRI for temporal lobe epilepsy

2019 ◽  
Vol 33 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Victor Schmidbauer ◽  
Silvia Bonelli
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Visual Memory ◽  
Imaging Modality ◽  
Memory Function ◽  
Brain Regions ◽  
Epileptogenic Zone ◽  
Brain Areas ◽  
Recent Developments ◽  
The Brain

AbstractEpilepsy is frequently accompanied by severe cognitive side effects. Temporal lobe epilepsy (TLE), and even successful surgical treatment, may affect cognitive function, in particular language as well as verbal and visual memory function. Epilepsy arising from the temporal lobe can be controlled surgically in up to 70% of patients. The goals of epilepsy surgery are to remove the brain areas generating the seizures without causing or aggravating neuropsychological deficits. This requires accurate localization of the brain areas generating the seizures (“epileptogenic zone”) and the areas responsible for motor and cognitive functions, such as language and memory (“essential brain regions”) during presurgical evaluation. In the past decades, functional magnetic resonance imaging (fMRI) has been increasingly used to noninvasively lateralize and localize not only primary motor and somatosensory areas, but also brain areas that are involved in everyday language and memory processes. The imaging modality also shows potential for predicting the effects of temporal lobe resection on language and memory function. Together with other MRI modalities, cognitive fMRI is a promising tool to improve surgical strategies tailored to individual patients with regard to functional outcome, by virtue of definition of epileptic cerebral areas that need to be resected and eloquent areas that need to be spared.The aim of this review is to provide an overview of recent developments and practical recommendations for the clinical use of cognitive fMRI in TLE.

scholarly journals Combined Parietal-Insular-Striatal Cortex Stroke with New-Onset Hallucinations: Supporting the Salience Network Model of Schizophrenia

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Saheba Nanda ◽  
Krishna Priya ◽  
Tasmia Khan ◽  
Puja Patel ◽  
Heela Azizi ◽  
...  
Keyword(s):  
Functional Integration ◽  
Insular Cortex ◽  
Brain Regions ◽  
Anterior Cingulate ◽  
Psychotic Symptoms ◽  
Salience Network ◽  
Schizophrenic Patients ◽  
Cortical Circuit ◽  
The Brain ◽  
New Onset

Brain imaging studies have identified multiple neuronal networks and circuits in the brain with altered functioning in patients with schizophrenia. These include the hippocampo-cerebello-cortical circuit, the prefrontal-thalamic-cerebellar circuit, functional integration in the bilateral caudate nucleus, and the salience network consisting of the insular cortex, parietal anterior cingulate cortex, and striatum, as well as limbic structures. Attributing psychotic symptoms to any of these networks in schizophrenia is confounded by the disruption of these networks in schizophrenic patients. Such attribution can be done with isolated dysfunction in any of these networks with concurrent psychotic symptoms. We present the case of a patient who presents with new-onset hallucinations and a stroke in brain regions similar to the salience network (insular cortex, parietal cortex, and striatum). The implication of these findings in isolating psychotic symptoms of the salience network is discussed.

Effective brain connectivity estimation between active brain regions in autism using the dual Kalman-based method

2020 ◽  
Vol 65 (1) ◽  
pp. 23-32
Author(s):  
Mehdi Rajabioun ◽  
Ali Motie Nasrabadi ◽  
Mohammad Bagher Shamsollahi ◽  
Robert Coben
Keyword(s):  
Resting State ◽  
Brain Connectivity ◽  
Effective Connectivity ◽  
Estimation Error ◽  
Brain Regions ◽  
Estimation Methods ◽  
Estimation Errors ◽  
Normal Children ◽  
Brain Functions ◽  
The Brain

AbstractBrain connectivity estimation is a useful method to study brain functions and diagnose neuroscience disorders. Effective connectivity is a subdivision of brain connectivity which discusses the causal relationship between different parts of the brain. In this study, a dual Kalman-based method is used for effective connectivity estimation. Because of connectivity changes in autism, the method is applied to autistic signals for effective connectivity estimation. For method validation, the dual Kalman based method is compared with other connectivity estimation methods by estimation error and the dual Kalman-based method gives acceptable results with less estimation errors. Then, connectivities between active brain regions of autistic and normal children in the resting state are estimated and compared. In this simulation, the brain is divided into eight regions and the connectivity between regions and within them is calculated. It can be concluded from the results that in the resting state condition the effective connectivity of active regions is decreased between regions and is increased within each region in autistic children. In another result, by averaging the connectivity between the extracted active sources of each region, the connectivity between the left and right of the central part is more than that in other regions and the connectivity in the occipital part is less than that in others.

Music, Maestro, Please: Thalamic multisensory integration in music perception, processing and production

2019 ◽  
Vol 11 (2) ◽  
pp. 98
Author(s):  
Artur Jaschke
Keyword(s):  
Multisensory Integration ◽  
Music Perception ◽  
Initial Point ◽  
Initial Step ◽  
Brain Regions ◽  
Thalamic Nuclei ◽  
Brain Areas ◽  
Neural Connections ◽  
Parietal Lobes ◽  
The Brain

Music activates a wide array of brain areas involved in different functions such as   perception, processing and execution of music. Understanding musical processes in the brain has multiple implications in the neuro- and health sciences.  Challenging the brain with a multisensory stimulus such as music activates responses beyond the auditory cortex of the temporal lobe. Other areas that are involved include the frontal lobes, parietal lobes, areas of the limbic system such as the amygdala, hippocampus and thalamus, the cerebellum and the brainstem. Nonetheless, there has been no attempt to summarize all involved brain areas in music into one overall encompassing map. This may well be, as there has been no thorough theory introduced, which would allow an initial point of departure in creating such a mapTherefore, a thorough systematic review has been conducted to identify all mentioned neural connections involved in the perception, processing and execution of music.  Communication between the thalamic nuclei is the initial step in multisensory integration, which lies at the base of the neural networks as proposed in this paper. Against this background, this manuscript introduces the to our knowledge first map of all brain regions involved in the perception, processing and execution of music.Consequently, placing thalamic multisensory integration at the core of this atlas allowed us to create a preliminary theory to explain the complexity of music induced brain activation.

scholarly journals A Core Set of Brain Regions Helps Kids Achieve Their Goals

2021 ◽  
Vol 9 ◽  
Author(s):  
AnnaCarolina Garza ◽  
Alice Aizza ◽  
Janchira K. Charoenworawat ◽  
Jessica A. Church
Keyword(s):  
Young People ◽  
Executive Functions ◽  
Brain Regions ◽  
Simple Games ◽  
Brain Areas ◽  
Core Set ◽  
The Brain

Your brain is always adjusting to the changing swirl of activities and interactions you have every day. Every time you accomplish a goal, you are exercising what are called the brain’s executive functions. These skills include resisting impulses, switching between tasks, and updating information in your memory. We asked whether these different skills relied on the same brain areas, and whether young people used the same brain areas as adults. We took pictures of kids’ and teens’ brains to see which areas of the brain they were using while they played three simple games related to these executive functions. We found that youth used similar brain regions to adults while playing the three games, and that many parts of the brain were used across all three games. These results help us understand how kids use their brains to be successful and how these skills develop.

scholarly journals Task-related effective connectivity reveals that the cortical rich club gates cortex-wide communication

2017 ◽  
Author(s):  
Mario Senden ◽  
Niels Reuter ◽  
Martijn P. van den Heuvel ◽  
Rainer Goebel ◽  
Gustavo Deco ◽  
...  
Keyword(s):  
Information Exchange ◽  
Effective Connectivity ◽  
Functional Integration ◽  
Brain Regions ◽  
Rich Club ◽  
State Dependent ◽  
Gating Mechanism ◽  
The Rich ◽  
Cortical Regions ◽  
Peripheral Regions

AbstractHigher cognition may require the globally coordinated integration of specialized brain regions into functional networks. A collection of structural cortical hubs - referred to as the rich club - has been hypothesized to support task-specific functional integration. In the present paper, we use a whole-cortex model to estimate directed interactions between 68 cortical regions from fMRI activity for four different tasks (reflecting different cognitive domains) and resting state. We analyze the state-dependent input and output effective connectivity of the structural rich club and relate these to whole-cortex dynamics and network reconfigurations. We find that the cortical rich club exhibits an increase in outgoing effective connectivity during task performance as compared to rest while incoming connectivity remains constant. Increased outgoing connectivity targets a sparse set of peripheral regions with specific regions strongly overlapping between tasks. At the same time, community detection analyses reveal massive reorganizations of interactions among peripheral regions, including those serving as target of increased rich club output. This suggests that while peripheral regions may play a role in several tasks, their concrete interplay might nonetheless be task-specific. Furthermore, we observe that whole-cortex dynamics are faster during task as compared to rest. The decoupling effects usually accompanying faster dynamics appear to be counteracted by the increased rich club outgoing effective connectivity. Together our findings speak to a gating mechanism of the rich club that supports fast-paced information exchange among relevant peripheral regions in a task-specific and goal-directed fashion, while constantly listening to the whole network.

scholarly journals Hemispheric Asymmetry of Human Brain Anatomical Network Revealed by Diffusion Tensor Tractography

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Ni Shu ◽  
Yaou Liu ◽  
Yunyun Duan ◽  
Kuncheng Li
Keyword(s):  
Human Brain ◽  
Large Scale ◽  
Diffusion Tensor ◽  
Functional Integration ◽  
Brain Regions ◽  
Hemispheric Asymmetries ◽  
Characteristic Path Length ◽  
Topological Measures ◽  
Structural Connections ◽  
The Brain

The topological architecture of the cerebral anatomical network reflects the structural organization of the human brain. Recently, topological measures based on graph theory have provided new approaches for quantifying large-scale anatomical networks. However, few studies have investigated the hemispheric asymmetries of the human brain from the perspective of the network model, and little is known about the asymmetries of the connection patterns of brain regions, which may reflect the functional integration and interaction between different regions. Here, we utilized diffusion tensor imaging to construct binary anatomical networks for 72 right-handed healthy adult subjects. We established the existence of structural connections between any pair of the 90 cortical and subcortical regions using deterministic tractography. To investigate the hemispheric asymmetries of the brain, statistical analyses were performed to reveal the brain regions with significant differences between bilateral topological properties, such as degree of connectivity, characteristic path length, and betweenness centrality. Furthermore, local structural connections were also investigated to examine the local asymmetries of some specific white matter tracts. From the perspective of both the global and local connection patterns, we identified the brain regions with hemispheric asymmetries. Combined with the previous studies, we suggested that the topological asymmetries in the anatomical network may reflect the functional lateralization of the human brain.

ELISA Evaluation of Tau Accumulation in the Brains of Patients with Alzheimer Disease

2021 ◽  
Author(s):  
Mitsuru Shinohara ◽  
Junko Hirokawa ◽  
Akemi Shimodaira ◽  
Yoshitaka Tashiro ◽  
Kaoru Suzuki ◽  
...  
Keyword(s):  
Alzheimer Disease ◽  
Brain Regions ◽  
Insoluble Fraction ◽  
The Other ◽  
Disease Stage ◽  
Brain Areas ◽  
Postmortem Brains ◽  
Biochemical Level ◽  
The Brain ◽  
Control Samples

Abstract Despite the routine use of sandwich enzyme-linked immunosorbent assays (ELISAs) for quantifying tau levels in CSF and plasma, tau accumulations in the brains of patients with Alzheimer disease (AD) have rarely been evaluated by this method. Thus, by introducing several tau ELISAs that target different epitopes, we evaluated accumulated tau levels in postmortem brains depending on disease stage, brain areas, and other AD-related changes. Notably, tau levels in insoluble fraction determined by each ELISAs differ depending on the epitopes of antibodies: non-AD control samples yield relatively high signals when an antibody against the N-terminal region of tau is used. On the other hand, ELISAs combining antibodies against the later-middle to C-terminal regions of tau produced substantially increased signals from AD samples, compared to those from non-AD controls. Such ELISAs better distinguish AD and non-AD controls, and the results are more closely associated with Braak neurofibrillary tangles stage, Aβ accumulation, and glial markers. Moreover, these ELISAs can reflect the pattern of tau spread across brain regions. In conclusion, Tau ELISAs that combine antibodies against the later-middle to C-terminal regions of tau can better reflect neuropathological tau accumulation, which would enable to evaluate tau accumulation in the brain at a biochemical level.

scholarly journals Imbalanced Dopaminergic Transmission Mediated by Serotonergic Neurons in L-DOPA-Induced Dyskinesia

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Sylvia Navailles ◽  
Philippe De Deurwaerdère
Keyword(s):  
Brain Regions ◽  
Term Treatment ◽  
Serotonergic Neurons ◽  
Brain Areas ◽  
Dopaminergic Transmission ◽  
The Core ◽  
Long Term Treatment ◽  
The Brain ◽  
Serotonergic Innervation

L-DOPA-induced dyskinesias (LIDs) are one of the main motor side effects of L-DOPA therapy in Parkinson's disease. The review will consider the biochemical evidence indicating that the serotonergic neurons are involved in the dopaminergic effects of L-DOPA in the brain. The consequences are an ectopic and aberrant release of dopamine that follows the serotonergic innervation of the brain. After mid- to long-term treatment with L-DOPA, the pattern of L-DOPA-induced dopamine release is modified. In several brain regions, its effect is dramatically reduced while, in the striatum, its effect is quite preserved. LIDs could appear when the dopaminergic effects of L-DOPA fall in brain areas such as the cortex, enhancing the subcortical impact of dopamine and promoting aberrant motor responses. The consideration of the serotonergic system in the core mechanism of action of L-DOPA opens an important reserve of possible strategies to limit LIDs.

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