scholarly journals Voxel-based morphometry and task functional magnetic resonance imaging in essential tremor: evidence for a disrupted brain network

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ilaria Boscolo Galazzo ◽  
Francesca Magrinelli ◽  
Francesca Benedetta Pizzini ◽  
Silvia Francesca Storti ◽  
Federica Agosta ◽  
...  
Keyword(s):  
Essential Tremor ◽  
Brain Network ◽  
Voxel Based Morphometry ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Motor Tasks ◽  
Subcortical Regions ◽  
Gray Matter Loss ◽  
Linear Regressions ◽  
And Task

Abstract The pathophysiology of essential tremor (ET) is controversial and might be further elucidated by advanced neuroimaging. Focusing on homogenous ET patients diagnosed according to the 2018 consensus criteria, this study aimed to: (1) investigate whether task functional MRI (fMRI) can identify networks of activated and deactivated brain areas, (2) characterize morphometric and functional modulations, relative to healthy controls (HC). Ten ET patients and ten HC underwent fMRI while performing two motor tasks with their upper limb: (1) maintaining a posture (both groups); (2) simulating tremor (HC only). Activations/deactivations were obtained from General Linear Model and compared across groups/tasks. Voxel-based morphometry and linear regressions between clinical and fMRI data were also performed. Few cerebellar clusters of gray matter loss were found in ET. Conversely, widespread fMRI alterations were shown. Tremor in ET (task 1) was associated with extensive deactivations mainly involving the cerebellum, sensory-motor cortex, and basal ganglia compared to both tasks in HC, and was negatively correlated with clinical tremor scales. Homogeneous ET patients demonstrated deactivation patterns during tasks triggering tremor, encompassing a network of cortical and subcortical regions. Our results point towards a marked cerebellar involvement in ET pathophysiology and the presence of an impaired cerebello-thalamo-cortical tremor network.

scholarly journals Greater BOLD Variability is Associated With Poorer Cognitive Function in an Adult Lifespan Sample

2020 ◽  
Vol 31 (1) ◽  
pp. 562-574
Author(s):  
Maria A Boylan ◽  
Chris M Foster ◽  
Ekarin E Pongpipat ◽  
Christina E Webb ◽  
Karen M Rodrigue ◽  
...  
Keyword(s):  
Healthy Aging ◽  
Blood Oxygenation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Adult Lifespan ◽  
Age Related ◽  
Oxygenation Level ◽  
Linear Slope ◽  
Subcortical Regions ◽  
Effects Of Aging

Abstract Moment-to-moment fluctuations in brain signal assessed by functional magnetic resonance imaging blood oxygenation level dependent (BOLD) variability is increasingly thought to represent important “signal” rather than measurement-related “noise.” Efforts to characterize BOLD variability in healthy aging have yielded mixed outcomes, demonstrating both age-related increases and decreases in BOLD variability and both detrimental and beneficial associations. Utilizing BOLD mean-squared-successive-differences (MSSD) during a digit n-back working memory (WM) task in a sample of healthy adults (aged 20–94 years; n = 171), we examined effects of aging on whole-brain 1) BOLD variability during task (mean condition MSSD across 0–2–3-4 back conditions), 2) BOLD variability modulation to incrementally increasing WM difficulty (linear slope from 0–2–3-4 back), and 3) the association of age-related differences in variability with in- and out-of-scanner WM performance. Widespread cortical and subcortical regions evidenced increased mean variability with increasing age, with no regions evidencing age-related decrease in variability. Additionally, posterior cingulate/precuneus exhibited increased variability to WM difficulty. Notably, both age-related increases in BOLD variability were associated with significantly poorer WM performance in all but the oldest adults. These findings lend support to the growing corpus suggesting that brain-signal variability is altered in healthy aging; specifically, in this adult lifespan sample, BOLD-variability increased with age and was detrimental to cognitive performance.

scholarly journals Measuring functional connectivity in stroke: Approaches and considerations

2017 ◽  
Vol 37 (8) ◽  
pp. 2665-2678 ◽  
Author(s):  
Joshua S Siegel ◽  
Gordon L Shulman ◽  
Maurizio Corbetta
Keyword(s):  
Functional Connectivity ◽  
Functional Organization ◽  
Brain Network ◽  
Global Changes ◽  
Brain Anatomy ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Non Invasive ◽  
Stroke Research ◽  
The Subject

Recent research has demonstrated the importance of global changes to the functional organization of brain network following stroke. Resting functional magnetic resonance imaging (R-fMRI) is a non-invasive tool that enables the measurement of functional connectivity (FC) across the entire brain while placing minimal demands on the subject. For these reasons, it is a uniquely appealing tool for studying the distant effects of stroke. However, R-fMRI studies rely on a number of premises that cannot be assumed without careful validation in the context of stroke. Here, we describe strategies to identify and mitigate confounds specific to R-fMRI research in cerebrovascular disease. Five main topics are discussed: (a) achieving adequate co-registration of lesioned brains, (b) identifying and removing hemodynamic lags in resting BOLD, (c) identifying other vascular disruptions that affect the resting BOLD signal, (d) selecting an appropriate control cohort, and (e) acquiring sufficient fMRI data to reliably identify FC changes. For each topic, we provide guidelines for steps to improve the interpretability and reproducibility of FC-stroke research. We include a table of confounds and approaches to identify and mitigate each. Our recommendations extend to any research using R-fMRI to study diseases that might alter cerebrovascular flow and dynamics or brain anatomy.

scholarly journals Acute Effect of Betel Quid Chewing on Brain Network Dynamics: A Resting-State Functional Magnetic Resonance Imaging Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaojun Huang ◽  
Zhipeng Wu ◽  
Zhening Liu ◽  
Dayi Liu ◽  
Danqing Huang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Resting State ◽  
Brain Network ◽  
Analysis Of Covariance ◽  
Betel Quid ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Switching Rate

Betel quid (BQ) is one of the most popular addictive substances in the world. However, the neurophysiological mechanism underlying BQ addiction remains unclear. This study aimed to investigate whether and how BQ chewing would affect brain function in the framework of a dynamic brain network model. Resting-state functional magnetic resonance imaging scans were collected from 24 male BQ-dependent individuals and 26 male non-addictive healthy individuals before and promptly after chewing BQ. Switching rate, a measure of temporal stability of functional brain networks, was calculated at both global and local levels for each scan. The results showed that BQ-dependent and healthy groups did not significantly differ on switching rate before BQ chewing (F = 0.784, p = 0.381, analysis of covariance controlling for age, education, and head motion). After chewing BQ, both BQ-dependent (t = 2.674, p = 0.014, paired t-test) and healthy (t = 2.313, p = 0.029, paired t-test) individuals showed a significantly increased global switching rate compared to those before chewing BQ. Significant corresponding local-level effects were observed within the occipital areas for both groups, and within the cingulo-opercular, fronto-parietal, and cerebellum regions for BQ-dependent individuals. Moreover, in BQ-dependent individuals, switching rate was significantly correlated with the severity of BQ addiction assessed by the Betel Quid Dependence Scale scores (Spearman's rho = 0.471, p = 0.020) before BQ chewing. Our study provides preliminary evidence for the acute effects of BQ chewing on brain functional dynamism. These findings may provide insights into the neural mechanisms of substance addictions.

scholarly journals Graph theory analysis of resting‐state functional magnetic resonance imaging in essential tremor

2019 ◽  
Vol 40 (16) ◽  
pp. 4686-4702 ◽  
Author(s):  
Julián Benito‐León ◽  
Emilio Sanz‐Morales ◽  
Helena Melero ◽  
Elan D. Louis ◽  
Juan P. Romero ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Graph Theory ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Essential Tremor ◽  
Resting State ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Theory Analysis ◽  
Graph Theory Analysis
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