Connectivity modulations induced by reach&grasp movements: a multidimensional approach

AbstractReach&grasp requires highly coordinated activation of different brain areas. We investigated whether reach&grasp kinematics is associated to EEG-based networks changes. We enrolled 10 healthy subjects. We analyzed the reach&grasp kinematics of 15 reach&grasp movements performed with each upper limb. Simultaneously, we obtained a 64-channel EEG, synchronized with the reach&grasp movement time points. We elaborated EEG signals with EEGLAB 12 in order to obtain event related synchronization/desynchronization (ERS/ERD) and lagged linear coherence between Brodmann areas. Finally, we evaluated network topology via sLORETA software, measuring network local and global efficiency (clustering and path length) and the overall balance (small-worldness). We observed a widespread ERD in α and β bands during reach&grasp, especially in the centro-parietal regions of the hemisphere contralateral to the movement. Regarding functional connectivity, we observed an α lagged linear coherence reduction among Brodmann areas contralateral to the arm involved in the reach&grasp movement. Interestingly, left arm movement determined widespread changes of α lagged linear coherence, specifically among right occipital regions, insular cortex and somatosensory cortex, while the right arm movement exerted a restricted contralateral sensory-motor cortex modulation. Finally, no change between rest and movement was found for clustering, path length and small-worldness. Through a synchronized acquisition, we explored the cortical correlates of the reach&grasp movement. Despite EEG perturbations, suggesting that the non-dominant reach&grasp network has a complex architecture probably linked to the necessity of a higher visual control, the pivotal topological measures of network local and global efficiency remained unaffected.

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Topological measures for identifying and predicting the spread of complex contagions

Nature Communications ◽

10.1038/s41467-021-24704-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Douglas Guilbeault ◽

Damon Centola

Keyword(s):

Social Networks ◽

Shortest Path ◽

Empirical Data ◽

Path Length ◽

Centrality Measures ◽

Social Phenomena ◽

Node Centrality ◽

Network Connectedness ◽

Topological Measures ◽

Definition Of

AbstractThe standard measure of distance in social networks – average shortest path length – assumes a model of “simple” contagion, in which people only need exposure to influence from one peer to adopt the contagion. However, many social phenomena are “complex” contagions, for which people need exposure to multiple peers before they adopt. Here, we show that the classical measure of path length fails to define network connectedness and node centrality for complex contagions. Centrality measures and seeding strategies based on the classical definition of path length frequently misidentify the network features that are most effective for spreading complex contagions. To address these issues, we derive measures of complex path length and complex centrality, which significantly improve the capacity to identify the network structures and central individuals best suited for spreading complex contagions. We validate our theory using empirical data on the spread of a microfinance program in 43 rural Indian villages.

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Dissociated Crossed Speech Areas in a Tumour Patient

Case Reports in Neurology ◽

10.1159/000475882 ◽

2017 ◽

Vol 9 (2) ◽

pp. 131-136 ◽

Cited By ~ 3

Author(s):

Jörg Mauler ◽

Irene Neuner ◽

Georg Neuloh ◽

Bruno Fimm ◽

Frank Boers ◽

...

Keyword(s):

Right Hemisphere ◽

Insular Cortex ◽

Low Grade ◽

Wada Test ◽

Brain Hemispheres ◽

Eloquent Areas ◽

Tumour Removal ◽

Frontal Operculum ◽

The Right ◽

Impaired Speech

In the past, the eloquent areas could be deliberately localised by the invasive Wada test. The very rare cases of dissociated crossed speech areas were accidentally found based on the clinical symptomatology. Today functional magnetic resonance imaging (fMRI)-based imaging can be employed to non-invasively localise the eloquent areas in brain tumour patients for therapy planning. A 41-year-old, left-handed man with a low-grade glioma in the left frontal operculum extending to the insular cortex, tension headaches, and anomic aphasia over 5 months underwent a pre-operative speech area localisation fMRI measurement, which revealed the evidence of the transhemispheric disposition, where the dominant Wernicke speech area is located on the left and the Broca’s area is strongly lateralised to the right hemisphere. The outcome of the Wada test and the intraoperative cortico-subcortical stimulation mapping were congruent with this finding. After tumour removal, language area function was fully preserved. Upon the occurrence of brain tumours with a risk of impaired speech function, the rare dissociate crossed speech areas disposition may gain a clinically relevant meaning by allowing for more extended tumour removal. Hence, for its identification, diagnostics which take into account both brain hemispheres, such as fMRI, are recommended.

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Experimental Evaluations of a Model of Mental Workload

Proceedings of the Human Factors Society Annual Meeting ◽

10.1177/154193128903301814 ◽

1989 ◽

Vol 33 (18) ◽

pp. 1233-1237 ◽

Cited By ~ 5

Author(s):

P. A. Hancock ◽

M. H. Chignell ◽

M. Vercruyssen ◽

M. Denhoff

Keyword(s):

Path Length ◽

Mental Workload ◽

Movement Time ◽

A Priori ◽

Independent Effect ◽

Subjective Perception ◽

Performance Task ◽

Related Factors ◽

Task Goal ◽

Systematic Effects

The present experiments were designed to test predictions from a model of mental workload. The model predicts non-linear increases in mental workload as perceived distance from a task goal grows and effective time for action is reduced. Diminution of mental workload is achieved by application of effort which brings the task goal into the region of acceptable time/distance constraints for successful resolution. Two experiments are reported which tested these assertions using the timepools performance task. Timepools is unique as a performance task in that it generates a spatial representation of a shrinking temporal target. The independent effects of path length, i.e., the number of sequential targets to be acquired, and shrink rate, i.e., the collapse time during which the circle is halved in area, may be assessed using performance variables such as reaction time (RT), movement time (MT), error rate (E), and the subjective perception of workload. Data from Experiment 1, indicate systematic effects for task related factors across performance and workload measures, although such a pattern was not isomorphically mapped to the a priori assumed difficulty of the task. In Experiment 2, shrink rate and path length had independent effect on RT and MT respectively, which were reflected in components of the individual workload scales. The ramifications with respect to the model are elaborated.

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Autonomic response after hemorrhagic stroke in the right insular cortex: What is the common pathophysiology in rat and human?; Reply

Autonomic Neuroscience ◽

10.1016/j.autneu.2021.102772 ◽

2021 ◽

Vol 231 ◽

pp. 102772

Author(s):

Fernanda Ribeiro Marins ◽

Marcelo Limborço-Filho ◽

Carlos Henrique Xavier ◽

Silvia Guatimosim ◽

Marco Antônio Peliky Fontes

Keyword(s):

Hemorrhagic Stroke ◽

Insular Cortex ◽

Autonomic Response ◽

The Common ◽

The Right

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Targeting in Virtual Workspaces: motor learning consolidates spatial memory for performance clusters

10.31234/osf.io/7z9q6 ◽

2019 ◽

Author(s):

Bradly Alicea ◽

Corey Bohil ◽

Frank Biocca ◽

Charles Owen

Keyword(s):

Repeated Measures ◽

Target Location ◽

Movement Time ◽

Three Dimensional ◽

Arm Movement ◽

Hierarchical Cluster ◽

Movement Speed ◽

Advantages And Disadvantages ◽

Training Interval ◽

Speed And Accuracy

Our objective was to focus on linkages between the process of learning and memory and the placement of objects within an array of targets in a virtual workspace. Participants were instructed to place virtual objects serially within a three-dimensional target array. One phase presented each target sequentially, and required participants to make timed ballistic arm movements. The other phase presented all nine targets simultaneously, which required ballistic arm movement towards the correct target location as recalled from the learning phase. Movement time and accuracy were assessed using repeated-measures ANOVA, a hierarchical cluster analysis, and a multiple linear regression. Collectively, this revealed numerous speed and accuracy advantages and disadvantages for various positional combinations. Upper positions universally yielded longer movement times and larger error measurements. Individual ability for mental rotation combined with task learning over a fixed training interval was found to predict accuracy for specific locations. The prediction that location influences movement speed and accuracy was supported, but with some caveats. These results may be particularly useful in the design of instructor stations and other hybrid physical-virtual workspaces.

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P14.23 Relation between neurological deficits and location of postsurgical ischemia in glioma resection

Neuro-Oncology ◽

10.1093/neuonc/noab180.145 ◽

2021 ◽

Vol 23 (Supplement_2) ◽

pp. ii42-ii42

Author(s):

A T J van der Boog ◽

S David ◽

A M M Steennis ◽

J W Dankbaar ◽

T J Snijders ◽

...

Keyword(s):

Corticospinal Tract ◽

Insular Cortex ◽

Spatial Relation ◽

Neurological Deficits ◽

Who Grade ◽

Basal Nuclei ◽

Supratentorial Glioma ◽

The Right ◽

Glioma Resection ◽

Patients Experience

Abstract BACKGROUND Postoperative ischemia is a known complications of glioma resection and can lead to neurological deficits. New or worsened postoperative deficits are often transient, but some patients experience persisting effects after surgery. Neuroanatomical location of ischemia is suspected to play an important role in the development as well as persistence of neurological deficits. Therefore, the aim of this study was to investigate the spatial relation between postoperative ischemia and short-term and long-term neurological deficits. MATERIAL AND METHODS Postoperative ischemia was defined as new confluent areas of diffusion restriction on DWI in a retrospective database of 144 adult WHO grade II-IV supratentorial glioma patients, who received MRI within 3 days after resection in 2012–2014. New or worsened neurological deficits of any grade at discharge and after 3 months was assessed in relation to postoperative ischemia by an experienced neuro-oncologist. We manually delineated ischemic lesions and spatially normalized these to stereotaxic MNI space. Next, we performed voxel-based analysis (VBA) to identify locations of ischemia associated with new or worsened neurological deficits and corrected for multiple comparisons using family-wise error correction to eliminate false positive results. Delineations were labeled using the Harvard-Oxford cortical and subcortical atlases and a white matter atlas (XTRACT). RESULTS Any new or worsened neurological deficits were present in 44 (30.5%) cases at discharge and in 27 (20.9%) cases after 3 months, of which respectively 26 (18%) and 21 (16.3%) were related to ischemia. Volume of ischemia was significantly associated with deficits at discharge (P = 0.003) and after 3 months (P = 0.039). No areas of ischemia were associated with a lack of new or worsened deficits. A statistically significant cluster of 42.96cc was associated with deficits at discharge and encompassed the right frontal, insular and tempo-occipital regions. Voxels associated only with deficits at discharge included lateral occipital cortices and supramarginal gyri. A cluster of 17.68cc in the right frontal and insular lobes was significantly associated with deficits after 3 months. Overlapping areas included the right thalamus, caudate nucleus, putamen, globus pallidum, insular cortex, middle and inferior temporal gyri, corticospinal tract and superior thalamic radiation. CONCLUSION Transient and persisting new or worsened deficits after glioma resection were significantly associated with volume of postoperative ischemia. Ischemic lesions in right frontal and insular regions, including the basal nuclei, corticospinal tract and superior thalamic radiation were significantly associated with persisting neurological deficits after 3 months, while temporo-occipital lesions were associated with transient deficits only found at discharge.

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Abstract 14192: Stroke Recurrence and Atrial Fibrillation Occurrence in the Patients With Right Insular Stroke

Circulation ◽

10.1161/circ.132.suppl_3.14192 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Hee-Kwon Park ◽

Sang-Bae Ko ◽

Joung-Ho Rha

Keyword(s):

Recurrence Rate ◽

Stroke Risk ◽

Insular Cortex ◽

Wave Dispersion ◽

P Wave ◽

Stroke Recurrence ◽

Stroke Patients ◽

P Wave Dispersion ◽

Arrhythmogenic Potential ◽

The Right

Introduction: The right insular cortical lesion is believed to have the arrhythmogenic potential such as secondary atrial fibrillation(AF). The P wave-triggered signal-averaged electrocardiogram(SA-ECG) can detect the P wave dispersion which is related to the risk of AF. The stroke risk of secondary AF after right insular stroke remained unclear. Hypothesis: We investigated the arrhythmogenic potential of right insular stroke, using SA-ECG and the stroke recurrence rate related to stroke location. Methods: We recruited acute stroke patients who admitted from February 2012 to October 2013 and took routine work-up, including SA-ECG. Patients who had the previous history of AF before admission, were excluded. We checked the stroke recurrence and AF occurrence over two years after index stroke. We analyzed the difference of SA-ECG, AF occurrence and stroke recurrence rate between the right insular cortex lesion and other stroke. Results: A total of 252 subjects were enrolled and 49 among them had right insular involvement. The patients with right insular lesion had longer P wave duration than the other stroke patients (154.0+29.6 vs. 133.5+26.5 ms, p<0.001). During observation period, stroke recurred in 28 patients and AF occurred in 50 persons. The patients with right insular lesion suffered from the AF occurrence and the stroke recurrence more frequently than those with other stroke lesions(AF occurrence, 33% vs 17%, P=0.01; Stroke Recurrence 25% vs 6%, P<0.01). Among the patients with AF occurrence, the patients with right insular lesion had the tendency of the higher stroke recurrence rate than those with the other stroke lesion(43.8% vs 20.6%, P=0.089). Conclusions: Our result suggests that the right insular lesion is related to increased P wave dispersion and this might explain the development of secondary AF after right insular cortex stroke. Secondary AF after right insular lesion might have the higher stroke risk than that after other stroke lesion.

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