scholarly journals The Effects of 10 Hz and 20 Hz tACS in Network Integration and Segregation in Chronic Stroke: A Graph Theoretical fMRI Study

2021 ◽  
Vol 11 (3) ◽  
pp. 377
Author(s):  
Cheng Chen ◽  
Kai Yuan ◽  
Winnie Chiu-wing Chu ◽  
Raymond Kai-yu Tong
Keyword(s):  
Chronic Stroke ◽  
Global Integration ◽  
Neural Responses ◽  
Whole Brain ◽  
Brain Level ◽  
Fmri Study ◽  
Transcranial Alternating Current Stimulation ◽  
Specific Stimulation ◽  
Clinical Potential ◽  
Local Segregation

Transcranial alternating current stimulation (tACS) has emerged as a promising technique to non-invasively modulate the endogenous oscillations in the human brain. Despite its clinical potential to be applied in routine rehabilitation therapies, the underlying modulation mechanism has not been thoroughly understood, especially for patients with neurological disorders, including stroke. In this study, we aimed to investigate the frequency-specific stimulation effect of tACS in chronic stroke. Thirteen chronic stroke patients underwent tACS intervention, while resting-state functional magnetic resonance imaging (fMRI) data were collected under various frequencies (sham, 10 Hz and 20 Hz). The graph theoretical analysis indicated that 20 Hz tACS might facilitate local segregation in motor-related regions and global integration at the whole-brain level. However, 10 Hz was only observed to increase the segregation from whole-brain level. Additionally, it is also observed that, for the network in motor-related regions, the nodal clustering characteristic was decreased after 10 Hz tACS, but increased after 20 Hz tACS. Taken together, our results suggested that tACS in various frequencies might induce heterogeneous modulation effects in lesioned brains. Specifically, 20 Hz tACS might induce more modulation effects, especially in motor-related regions, and they have the potential to be applied in rehabilitation therapies to facilitate neuromodulation. Our findings might shed light on the mechanism of neural responses to tACS and facilitate effectively designing stimulation protocols with tACS in stroke in the future.

scholarly journals Disrupted Topological Organization in Whole-Brain Functional Networks of Heroin-Dependent Individuals: A Resting-State fMRI Study

PLoS ONE ◽  
2013 ◽  
Vol 8 (12) ◽  
pp. e82715 ◽  
Author(s):  
Guihua Jiang ◽  
Xue Wen ◽  
Yingwei Qiu ◽  
Ruibin Zhang ◽  
Junjing Wang ◽  
...  
Keyword(s):  
Resting State ◽  
Resting State Fmri ◽  
Functional Networks ◽  
Whole Brain ◽  
Brain Functional Networks ◽  
Fmri Study ◽  
Topological Organization

The Time Course of Changes during Motor Sequence Learning: A Whole-Brain fMRI Study

NeuroImage ◽  
1998 ◽  
Vol 8 (1) ◽  
pp. 50-61 ◽  
Author(s):  
Ivan Toni ◽  
Michael Krams ◽  
Robert Turner ◽  
Richard E. Passingham
Keyword(s):  
Sequence Learning ◽  
Time Course ◽  
Motor Sequence Learning ◽  
Motor Sequence ◽  
Whole Brain ◽  
Fmri Study ◽  
Brain Fmri

scholarly journals Exploring the dynamic mechanisms of steady-state visual evoked potentials at the whole-brain level: evidence from a computational study

2021 ◽  
Author(s):  
Ge Zhang ◽  
Yan Cui ◽  
Yangsong Zhang ◽  
Hefei Cao ◽  
Guanyu Zhou ◽  
...  
Keyword(s):  
Steady State ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Large Scale ◽  
Whole Brain ◽  
Frequency Sensitivity ◽  
Dynamic Mechanisms ◽  
Brain Level ◽  
The Brain ◽  
Visual Evoked

AbstractPeriodic visual stimulation can induce stable steady-state visual evoked potentials (SSVEPs) distributed in multiple brain regions and has potential applications in both neural engineering and cognitive neuroscience. However, the underlying dynamic mechanisms of SSVEPs at the whole-brain level are still not completely understood. Here, we addressed this issue by simulating the rich dynamics of SSVEPs with a large-scale brain model designed with constraints of neuroimaging data acquired from the human brain. By eliciting activity of the occipital areas using an external periodic stimulus, our model was capable of replicating both the spatial distributions and response features of SSVEPs that were observed in experiments. In particular, we confirmed that alpha-band (8-12 Hz) stimulation could evoke stronger SSVEP responses; this frequency sensitivity was due to nonlinear resonance and could be modulated by endogenous factors in the brain. Interestingly, the stimulus-evoked brain networks also exhibited significant superiority in topological properties near this frequency-sensitivity range, and stronger SSVEP responses were demonstrated to be supported by more efficient functional connectivity at the neural activity level. These findings not only provide insights into the mechanistic understanding of SSVEPs at the whole-brain level but also indicate a bright future for large-scale brain modeling in characterizing the complicated dynamics and functions of the brain.

scholarly journals P1-125: EVALUATING RESTING STATE CONNECTIVITY HERITABILITY AT THE WHOLE BRAIN LEVEL

2019 ◽  
Vol 15 ◽  
pp. P282-P283
Author(s):  
Arman P. Kulkarni ◽  
Cole John Cook ◽  
Gyujoon Hwang ◽  
Veena A. Nair ◽  
Elizabeth M. Meyerand ◽  
...  
Keyword(s):  
Resting State ◽  
Whole Brain ◽  
Brain Level ◽  
Resting State Connectivity

Boys’ toys, girls’ toys: An fMRI study of mothers’ neural responses to children violating gender expectations

2019 ◽  
Vol 148 ◽  
pp. 107776 ◽  
Author(s):  
Joyce J. Endendijk ◽  
Anne K. Smit ◽  
Anneloes L. van Baar ◽  
Peter A. Bos
Keyword(s):  
Neural Responses ◽  
Gender Expectations ◽  
Fmri Study

scholarly journals Global integration of local color differences in transparency perception: An fMRI study

2006 ◽  
Vol 23 (3-4) ◽  
pp. 357-364 ◽  
Author(s):  
MICHEL DOJAT ◽  
LOŸS PIETTRE ◽  
CHANTAL DELON-MARTIN ◽  
MATHILDE PACHOT-CLOUARD ◽  
CHRISTOPH SEGEBARTH ◽  
...  
Keyword(s):  
Anterior Part ◽  
Cortical Activation ◽  
Parahippocampal Gyrus ◽  
Global Integration ◽  
Local Color ◽  
Perceptual Integration ◽  
Geometric Patterns ◽  
Fmri Study ◽  
Color Differences ◽  
Cortical Regions

In normal viewing, the visual system effortlessly assigns approximately constant attributes of color and shape to perceived objects. A fundamental component of this process is the compensation for illuminant variations and intervening media to recover reflectance properties of natural surfaces. We exploited the phenomenon of transparency perception to explore the cortical regions implicated in such processes, using fMRI. By manipulating the coherence of local color differences around a region in an image, we interfered with their global perceptual integration and thereby modified whether the region appeared transparent or not. We found the major cortical activation due to global integration of local color differences to be in the anterior part of the parahippocampal gyrus. Regions differentially activated by chromatic versus achromatic geometric patterns showed no significant differential response related to the coherence/incoherence of local color differences. The results link the integration of local color differences in the extraction of a transparent layer with sites activated by object-related properties of an image.

scholarly journals Differences in neural responses to reward and punishment processing between anorexia nervosa subtypes: An fMRI study

2017 ◽  
Vol 71 (9) ◽  
pp. 647-658 ◽  
Author(s):  
Ema Murao ◽  
Genichi Sugihara ◽  
Masanori Isobe ◽  
Tomomi Noda ◽  
Michiko Kawabata ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Neural Responses ◽  
Fmri Study ◽  
Reward And Punishment
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