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Reliability and reproducibility of individual differences in functional connectivity acquired during task and resting state.

Shah LM, Cramer JA, Ferguson MA, Birn RM, Anderson JS - Brain Behav (2016)

Bottom Line: Randomly removing up to 50% of time points had little effect on reliability, while truncating an acquisition was associated with decreased reliability.This study found systematic differences in group-mean connectivity acquired during task and rest acquitisions and preserved individual differences in connectivity due to intrinsic differences in an individual's brain activity and structural brain architecture.Longer scans may be facilitated by acquisition during task paradigms, which will systematically affect functional connectivity but may preserve individual differences in connectivity on top of task modulations.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology University of Utah Salt Lake City Utah 84132.

ABSTRACT

Objectives: Application of fMRI connectivity metrics as diagnostic biomarkers at the individual level will require reliability, sensitivity and specificity to longitudinal changes in development, aging, neurocognitive, and behavioral performance and pathologies. Such metrics have not been well characterized for recent advances in BOLD acquisition.

Experimental design: Analysis of multiband BOLD data from the HCP 500 Subjects Release was performed with FIX ICA and with WM, CSF and motion parameter regression. Analysis with ROIs covering the gray matter at 5 mm resolution was performed to assess functional connectivity. ROIs in key areas were used to demonstrate statistical differences between specific connections. Reproducibility of group-mean functional connectivity and for single connections for individuals was evaluated for both resting state and task acquisitions.

Principal observations: Systematic differences in group-mean connectivity were demonstrated during task and rest and during different tasks, although individual differences in connectivity were maintained. Reproducibility of a single connection for a subject and across subjects for resting and task acquisition was demonstrated to be a linear function of the square root of imaging time. Randomly removing up to 50% of time points had little effect on reliability, while truncating an acquisition was associated with decreased reliability. Reliability was highest within the cortex, and lowest for deep gray nuclei, gray-white junction, and near large sulci.

Conclusions: This study found systematic differences in group-mean connectivity acquired during task and rest acquitisions and preserved individual differences in connectivity due to intrinsic differences in an individual's brain activity and structural brain architecture. We also show that longer scan times are needed to acquire data on single subjects for information on connections between specific ROIs. Longer scans may be facilitated by acquisition during task paradigms, which will systematically affect functional connectivity but may preserve individual differences in connectivity on top of task modulations.

No MeSH data available.


Related in: MedlinePlus

Effect of two strategies of data removal on reliability is shown. Intraclass correlation coefficient is shown for functional connectivity measurements from two seeds (left posterior cingulate, above; right precentral gyrus, below) to 264 ROIs after sequentially removing up to half of the volumes in the time series. Red curves (scrubbing) represent removal of randomly selected points in the time series. Blue curves (truncating) represent inclusion of timepoints from the beginning of the scan. Reliability is only minimally affected for scrubbing, even with removal of half of the data points. However, truncating the time series with removal of time points from the end of the time series shows much larger effects on reliability of functional connectivity measurements.
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brb3456-fig-0006: Effect of two strategies of data removal on reliability is shown. Intraclass correlation coefficient is shown for functional connectivity measurements from two seeds (left posterior cingulate, above; right precentral gyrus, below) to 264 ROIs after sequentially removing up to half of the volumes in the time series. Red curves (scrubbing) represent removal of randomly selected points in the time series. Blue curves (truncating) represent inclusion of timepoints from the beginning of the scan. Reliability is only minimally affected for scrubbing, even with removal of half of the data points. However, truncating the time series with removal of time points from the end of the time series shows much larger effects on reliability of functional connectivity measurements.

Mentions: Intraclass correlation coefficient was calculated for each ROI in each subject with “simulated scrubbing” where randomly selected data volumes were removed showed almost no effect on reliability. However, truncation of the time series by a similar number of volumes had dramatic effect on reliability, shown in Figure 6, indicating that the key factor affecting reliability is scan duration, not necessarily the number of volumes used for analysis.


Reliability and reproducibility of individual differences in functional connectivity acquired during task and resting state.

Shah LM, Cramer JA, Ferguson MA, Birn RM, Anderson JS - Brain Behav (2016)

Effect of two strategies of data removal on reliability is shown. Intraclass correlation coefficient is shown for functional connectivity measurements from two seeds (left posterior cingulate, above; right precentral gyrus, below) to 264 ROIs after sequentially removing up to half of the volumes in the time series. Red curves (scrubbing) represent removal of randomly selected points in the time series. Blue curves (truncating) represent inclusion of timepoints from the beginning of the scan. Reliability is only minimally affected for scrubbing, even with removal of half of the data points. However, truncating the time series with removal of time points from the end of the time series shows much larger effects on reliability of functional connectivity measurements.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814225&req=5

brb3456-fig-0006: Effect of two strategies of data removal on reliability is shown. Intraclass correlation coefficient is shown for functional connectivity measurements from two seeds (left posterior cingulate, above; right precentral gyrus, below) to 264 ROIs after sequentially removing up to half of the volumes in the time series. Red curves (scrubbing) represent removal of randomly selected points in the time series. Blue curves (truncating) represent inclusion of timepoints from the beginning of the scan. Reliability is only minimally affected for scrubbing, even with removal of half of the data points. However, truncating the time series with removal of time points from the end of the time series shows much larger effects on reliability of functional connectivity measurements.
Mentions: Intraclass correlation coefficient was calculated for each ROI in each subject with “simulated scrubbing” where randomly selected data volumes were removed showed almost no effect on reliability. However, truncation of the time series by a similar number of volumes had dramatic effect on reliability, shown in Figure 6, indicating that the key factor affecting reliability is scan duration, not necessarily the number of volumes used for analysis.

Bottom Line: Randomly removing up to 50% of time points had little effect on reliability, while truncating an acquisition was associated with decreased reliability.This study found systematic differences in group-mean connectivity acquired during task and rest acquitisions and preserved individual differences in connectivity due to intrinsic differences in an individual's brain activity and structural brain architecture.Longer scans may be facilitated by acquisition during task paradigms, which will systematically affect functional connectivity but may preserve individual differences in connectivity on top of task modulations.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology University of Utah Salt Lake City Utah 84132.

ABSTRACT

Objectives: Application of fMRI connectivity metrics as diagnostic biomarkers at the individual level will require reliability, sensitivity and specificity to longitudinal changes in development, aging, neurocognitive, and behavioral performance and pathologies. Such metrics have not been well characterized for recent advances in BOLD acquisition.

Experimental design: Analysis of multiband BOLD data from the HCP 500 Subjects Release was performed with FIX ICA and with WM, CSF and motion parameter regression. Analysis with ROIs covering the gray matter at 5 mm resolution was performed to assess functional connectivity. ROIs in key areas were used to demonstrate statistical differences between specific connections. Reproducibility of group-mean functional connectivity and for single connections for individuals was evaluated for both resting state and task acquisitions.

Principal observations: Systematic differences in group-mean connectivity were demonstrated during task and rest and during different tasks, although individual differences in connectivity were maintained. Reproducibility of a single connection for a subject and across subjects for resting and task acquisition was demonstrated to be a linear function of the square root of imaging time. Randomly removing up to 50% of time points had little effect on reliability, while truncating an acquisition was associated with decreased reliability. Reliability was highest within the cortex, and lowest for deep gray nuclei, gray-white junction, and near large sulci.

Conclusions: This study found systematic differences in group-mean connectivity acquired during task and rest acquitisions and preserved individual differences in connectivity due to intrinsic differences in an individual's brain activity and structural brain architecture. We also show that longer scan times are needed to acquire data on single subjects for information on connections between specific ROIs. Longer scans may be facilitated by acquisition during task paradigms, which will systematically affect functional connectivity but may preserve individual differences in connectivity on top of task modulations.

No MeSH data available.


Related in: MedlinePlus