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Quantitative assessment of visual cortex function with fMRI at 7 Tesla-test-retest variability.

Abd Hamid AI, Speck O, Hoffmann MB - Front Hum Neurosci (2015)

Bottom Line: We found a reduction between Sessions 1 and 2 for activated cortical surface area, between Sessions 1 and 3 for amplitude, and between Sessions 1 and 2/3 for coherence.The results do not support head motion as a major cause of the observed effect seen in Session 1, suggesting that cognitive effects were the underlying cause of change.This experimental design provides guidance in methodological issues of clinical longitudinal fMRI-studies, specifically regarding effects of subject experience.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg Magdeburg, Germany ; Department of Neurosciences, School of Medical Sciences Health Campus, Universiti Sains Malaysia Kubang Kerian, Malaysia.

ABSTRACT
fMRI-based retinotopic mapping was used to assess systematic variations in activated cortical surface area, amplitude, and coherence across sessions. Seven healthy subjects were scanned at 7 T in three separate sessions with intervals of 51.4 ± 5.4 days (Sessions 1 and 2) and 167.9 ± 24.4 days (Sessions 2 and 3). We found a reduction between Sessions 1 and 2 for activated cortical surface area, between Sessions 1 and 3 for amplitude, and between Sessions 1 and 2/3 for coherence. The results do not support head motion as a major cause of the observed effect seen in Session 1, suggesting that cognitive effects were the underlying cause of change. The phase correlations for both eccentricity and polar angle mapping were highly correlated between sessions, demonstrating the stability of the maps. Furthermore, the sensitivity in determining inter-session changes of cortical surface area, response amplitude, and coherence were, at a 5% significance level, estimated to be 1.5, 6, and 5%, respectively. Any future longitudinal fMRI study should carefully evaluate activation across sessions to determine the eligibility of inclusion of all time points. This experimental design provides guidance in methodological issues of clinical longitudinal fMRI-studies, specifically regarding effects of subject experience.

No MeSH data available.


Related in: MedlinePlus

Quantitative comparison of correlation of phase maps (re-transformed mean ± SEM of Z-transformed value) of between sessions 1 and 2, and between sessions 2 and 3 within defined visual for eccentricity and polar angle. No significant effects were observed as detailed in Results.
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Figure 5: Quantitative comparison of correlation of phase maps (re-transformed mean ± SEM of Z-transformed value) of between sessions 1 and 2, and between sessions 2 and 3 within defined visual for eccentricity and polar angle. No significant effects were observed as detailed in Results.

Mentions: The phase map similarity or reproducibility within defined visual areas for eccentricity and polar angle were determined (1) between sessions 1 and 2 (S1S2) and (2) between sessions 2 and 3 (S2S3). We applied a threshold of p = 0.05 for all visual areas in both sessions for these analyses. Figure 5 shows the mean correlation coefficient of S1S2 and S2S3 within the visual areas for eccentricity and polar angle. The results showed that phase maps in V1, V2, and V3, for both eccentricity and polar angle, were highly correlated, with a mean correlation coefficient >0.70. This is in agreement with a previous studies on intra-session variability (Hoffmann et al., 2012) and exceeds the value of a study on inter-session variability (Swisher et al., 2007).


Quantitative assessment of visual cortex function with fMRI at 7 Tesla-test-retest variability.

Abd Hamid AI, Speck O, Hoffmann MB - Front Hum Neurosci (2015)

Quantitative comparison of correlation of phase maps (re-transformed mean ± SEM of Z-transformed value) of between sessions 1 and 2, and between sessions 2 and 3 within defined visual for eccentricity and polar angle. No significant effects were observed as detailed in Results.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555013&req=5

Figure 5: Quantitative comparison of correlation of phase maps (re-transformed mean ± SEM of Z-transformed value) of between sessions 1 and 2, and between sessions 2 and 3 within defined visual for eccentricity and polar angle. No significant effects were observed as detailed in Results.
Mentions: The phase map similarity or reproducibility within defined visual areas for eccentricity and polar angle were determined (1) between sessions 1 and 2 (S1S2) and (2) between sessions 2 and 3 (S2S3). We applied a threshold of p = 0.05 for all visual areas in both sessions for these analyses. Figure 5 shows the mean correlation coefficient of S1S2 and S2S3 within the visual areas for eccentricity and polar angle. The results showed that phase maps in V1, V2, and V3, for both eccentricity and polar angle, were highly correlated, with a mean correlation coefficient >0.70. This is in agreement with a previous studies on intra-session variability (Hoffmann et al., 2012) and exceeds the value of a study on inter-session variability (Swisher et al., 2007).

Bottom Line: We found a reduction between Sessions 1 and 2 for activated cortical surface area, between Sessions 1 and 3 for amplitude, and between Sessions 1 and 2/3 for coherence.The results do not support head motion as a major cause of the observed effect seen in Session 1, suggesting that cognitive effects were the underlying cause of change.This experimental design provides guidance in methodological issues of clinical longitudinal fMRI-studies, specifically regarding effects of subject experience.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg Magdeburg, Germany ; Department of Neurosciences, School of Medical Sciences Health Campus, Universiti Sains Malaysia Kubang Kerian, Malaysia.

ABSTRACT
fMRI-based retinotopic mapping was used to assess systematic variations in activated cortical surface area, amplitude, and coherence across sessions. Seven healthy subjects were scanned at 7 T in three separate sessions with intervals of 51.4 ± 5.4 days (Sessions 1 and 2) and 167.9 ± 24.4 days (Sessions 2 and 3). We found a reduction between Sessions 1 and 2 for activated cortical surface area, between Sessions 1 and 3 for amplitude, and between Sessions 1 and 2/3 for coherence. The results do not support head motion as a major cause of the observed effect seen in Session 1, suggesting that cognitive effects were the underlying cause of change. The phase correlations for both eccentricity and polar angle mapping were highly correlated between sessions, demonstrating the stability of the maps. Furthermore, the sensitivity in determining inter-session changes of cortical surface area, response amplitude, and coherence were, at a 5% significance level, estimated to be 1.5, 6, and 5%, respectively. Any future longitudinal fMRI study should carefully evaluate activation across sessions to determine the eligibility of inclusion of all time points. This experimental design provides guidance in methodological issues of clinical longitudinal fMRI-studies, specifically regarding effects of subject experience.

No MeSH data available.


Related in: MedlinePlus