scholarly journals Spontaneous low-frequency BOLD signal fluctuations: An fMRI investigation of the resting-state default mode of brain function hypothesis

2005 ◽  
Vol 26 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Peter Fransson
Keyword(s):  
Resting State ◽  
Brain Function ◽  
Low Frequency ◽  
Bold Signal ◽  
Default Mode

Analysis of connectivity in the resting state of the default mode of brain function: a major role for the cerebellum?

2010 ◽  
Vol 9 (3) ◽  
pp. 236
Author(s):  
Yazhuo Kong ◽  
Tirthankar Mukherjee ◽  
Shane McKie ◽  
J.F. William Deakin ◽  
Steve Williams
Keyword(s):  
Resting State ◽  
Brain Function ◽  
Default Mode

scholarly journals Subcortical connectivity in dementia with Lewy bodies and Alzheimer's disease

2013 ◽  
Vol 203 (3) ◽  
pp. 209-214 ◽  
Author(s):  
Eva R. Kenny ◽  
John T. O'Brien ◽  
Michael J. Firbank ◽  
Andrew M. Blamire
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Resting State ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Low Frequency ◽  
Blood Oxygen Level Dependent ◽  
Bold Signal ◽  
Blood Oxygen Level

BackgroundResting-state functional magnetic resonance imaging (fMRI) can be used to measure correlations in spontaneous low-frequency fluctuations in the blood oxygen level-dependent (BOLD) signal which represent functional connectivity between key brain areas.AimsTo investigate functional connectivity with regions hypothesised to be differentially affected in dementia with Lewy bodies (DLB) compared with Alzheimer's disease and controls.MethodFifteen participants with probable DLB, 16 with probable Alzheimer's disease and 16 controls were scanned in the resting-state using a 3T scanner. The BOLD signal time-series of fluctuations in seed regions were correlated with all other voxels to measure functional connectivity.ResultsParticipants with DLB and Alzheimer's disease showed greater caudate and thalamic connectivity compared with controls. Those with DLB showed greater putamen connectivity compared with those with Alzheimer's disease and the controls. No regions showed less connectivity in DLB or Alzheimer's disease v. controls, or in DLB v. Alzheimer's disease.ConclusionsAltered connectivity in DLB and Alzheimer's disease provides new insights into the neurobiology of these disorders and may aid in earlier diagnosis.

scholarly journals P119 Brain function and fatigue in patients with inflammatory bowel disease

2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S195-S196
Author(s):  
A Thomann ◽  
M Schmitgen ◽  
D Kmuche ◽  
M Griebe ◽  
M Ebert ◽  
...  
Keyword(s):  
Resting State ◽  
Brain Function ◽  
Brain Activity ◽  
Low Frequency ◽  
Peak Level ◽  
Brain Regions ◽  
Fmri Data ◽  
Considerable Proportion ◽  
Functional Studies ◽  
Inflammatory Bowel

Abstract Background Fatigue is common in patients with inflammatory bowel diseases (IBD). It occurs in up to 80% of patients with active disease, but also a considerable proportion of patients in remission, and significantly affects quality of life. The underlying mechanisms are still poorly understood, and it is still unclear which patients will suffer from fatigue even in luminally quiescent disease. Task-based brain functional studies have examined neural correlates of fatigueability and found changes in the orbitofrontal cortex (OFC), among other regions. To the best our knowledge, the relationship between brain function and fatigue in IBD has not been investigated. This study aimed to examine the association between fatigue and resting-state brain function in remitted IBD patients. Methods We obtained resting-state-functional MRI (rs-fMRI) data from 45 IBD patients in stable remission without current steroid or biological therapy and 17 healthy controls (HCs). Fatigue was assessed with Würzburger Erschöpfungsinventar Multiple Sklerose (WEIMuS). Preprocessing of rs-fMRI-data and calculation of amplitude of low frequency fluctuations (ALFF) was performed using the Data Processing Assistant for rs-fMRI. The resulting individual maps were analysed via second-level SPM multiple regression models in patients and HC to test for correlations between ALFF data and WEIMuS scores. Age, gender and mean framewise displacement were included as covariates of no interest and results were displayed at p < 0.001 (peak level) with a threshold of spatial extent (k) according to the expected voxels per cluster estimated by SPM. Results Fatigue scores did not differ significantly between patients and controls (mean WEIMuS-scores 17.9 (SD 13.9) vs. 12.3 (SD 16.5), p = .17). Proportions of participants with fatigue scores above the cutoff (>32P.) were nearly identical in patients and HC (8/45 vs. 3/17). In patients, fatigue scores correlated positively with ALFF in the right central operculum and negatively with ALFF in the left OFC and left cerebellum (all p < .001, Figure 1). Fatigue and ALFF in the left cerebellum were also found to correlate in HC. Conclusion This study shows fatigue-associated changes in brain activity in several brain regions. The negative association between fatigue and ALFF in the left OFC of IBD patients was not seen in HC, indicating that reduced ALFF in the OFC may represent a neural correlate of IBD-related fatigue. The OFC is thought to be involved in decision-making, which is described to be impaired in many fatigued IBD patients. If the association between fatigue and brain function detected in our study is confirmed in longitudinal IBD studies, these regions could serve as biomarkers when targeting fatigue in IBD.

Correction of low-frequency physiological noise from the resting state BOLD fMRI—Effect on ICA default mode analysis at 1.5T

2010 ◽  
Vol 186 (2) ◽  
pp. 179-185 ◽  
Author(s):  
Tuomo Starck ◽  
Jukka Remes ◽  
Juha Nikkinen ◽  
Osmo Tervonen ◽  
Vesa Kiviniemi
Keyword(s):  
Resting State ◽  
Low Frequency ◽  
Mode Analysis ◽  
Physiological Noise ◽  
Bold Fmri ◽  
Default Mode

Independent component model of the default-mode brain function: combining individual-level and population-level analyses in resting-state fMRI

2008 ◽  
Vol 26 (7) ◽  
pp. 905-913 ◽  
Author(s):  
Fabrizio Esposito ◽  
Adriana Aragri ◽  
Ilaria Pesaresi ◽  
Sossio Cirillo ◽  
Gioacchino Tedeschi ◽  
...  
Keyword(s):  
Resting State ◽  
Brain Function ◽  
Population Level ◽  
Resting State Fmri ◽  
Independent Component ◽  
Component Model ◽  
Default Mode ◽  
Individual Level

scholarly journals Task-evoked Negative BOLD Response and Functional Connectivity in the Default Mode Network are Representative of Two Overlapping but Separate Neurophysiological Processes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
David B. Parker ◽  
Qolamreza R. Razlighi
Keyword(s):  
Functional Connectivity ◽  
Default Mode Network ◽  
Resting State ◽  
Low Frequency ◽  
Brain Regions ◽  
Intrinsic Activity ◽  
Bold Response ◽  
Default Mode ◽  
Macro Scale ◽  
Negative Bold

Abstract The topography of the default mode network (DMN) can be obtained with one of two different functional magnetic resonance imaging (fMRI) methods: either from the spontaneous but organized synchrony of the low-frequency fluctuations in resting-state fMRI (rs-fMRI), known as “functional connectivity”, or from the consistent and robust deactivations in task-based fMRI (tb-fMRI), here referred to as the “negative BOLD response” (NBR). These two methods are fundamentally different, but their results are often used interchangeably to describe the brain’s resting-state, baseline, or intrinsic activity. While the DMN was initially defined by consistent task-based decreases in blood flow in a set of specific brain regions using PET imaging, recently nearly all studies on the DMN employ functional connectivity in rs-fMRI. In this study, we first show the high level of spatial overlap between NBR and functional connectivity of the DMN extracted from the same tb-fMRI scan; then, we demonstrate that the NBR in putative DMN regions can be significantly altered without causing any change in their overlapping functional connectivity. Furthermore, we present evidence that in the DMN, the NBR is more closely related to task performance than the functional connectivity. We conclude that the NBR and functional connectivity of the DMN reflect two separate but overlapping neurophysiological processes, and thus should be differentiated in studies investigating brain-behavior relationships in both healthy and diseased populations. Our findings further raise the possibility that the macro-scale networks of the human brain might internally exhibit a hierarchical functional architecture.

scholarly journals Propofol attenuates low-frequency fluctuations of resting-state fMRI BOLD signal in the anterior frontal cortex upon loss of consciousness

NeuroImage ◽  
2017 ◽  
Vol 147 ◽  
pp. 295-301 ◽  
Author(s):  
Xiaolin Liu ◽  
Kathryn K. Lauer ◽  
B. Douglas Ward ◽  
Christopher Roberts ◽  
Suyan Liu ◽  
...  
Keyword(s):  
Frontal Cortex ◽  
Resting State ◽  
Low Frequency ◽  
Resting State Fmri ◽  
Loss Of Consciousness ◽  
Bold Signal ◽  
Frequency Fluctuations
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