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help > Second level analysis (ROI-to-ROI) and beta values
Nov 7, 2019 10:11 AM | hannasofia - Gothenburg university
Second level analysis (ROI-to-ROI) and beta values
Hello,
I'm looking for some information about interpreting second level analysis, and to perform group comparisons.
I'm investigating whether a difference in connectivity can be seen in patients compared to controls in ROI-to ROI analysis (n=20).
Settings in 1st level analysis is: functional connectivity, ROI-to-ROI analysis, correlation (bivariate) with no weighing. Two seeds/sources are chosen.
Settings in 2nd level analysis are; Subject effect (I have marked condition patients and controls already prepared in Setup conditions). Between-subjects contrast [1 0; 0 1] (Any effect among controls or patiens), between-conditions contrast =1 and between-sources contrast=1.
Results explorer I see F(2) (18) = 51.80 p ung and p FWE =0.000. In a results explorer from another date I got a T-value of 4.85 instead. Why has it changed the statistics and what do I do with this data?
How do I interpret this? What is the connectivity in patients compared to controls? Is the difference significant?
My other questions concerns the beta-values for each individual subject. What is the beta value and how do I convert it into a connectivity value? I find the beta values in the first level analysis folder in the matrix need "Z". But which of all these values should look at?
I plan to add more Seeds/sources in time. Do I need to change anything in the settings if I do so??
Attached file is the first level analysis results for one subject.
Thank you very much for your time,
BR
I'm looking for some information about interpreting second level analysis, and to perform group comparisons.
I'm investigating whether a difference in connectivity can be seen in patients compared to controls in ROI-to ROI analysis (n=20).
Settings in 1st level analysis is: functional connectivity, ROI-to-ROI analysis, correlation (bivariate) with no weighing. Two seeds/sources are chosen.
Settings in 2nd level analysis are; Subject effect (I have marked condition patients and controls already prepared in Setup conditions). Between-subjects contrast [1 0; 0 1] (Any effect among controls or patiens), between-conditions contrast =1 and between-sources contrast=1.
Results explorer I see F(2) (18) = 51.80 p ung and p FWE =0.000. In a results explorer from another date I got a T-value of 4.85 instead. Why has it changed the statistics and what do I do with this data?
How do I interpret this? What is the connectivity in patients compared to controls? Is the difference significant?
My other questions concerns the beta-values for each individual subject. What is the beta value and how do I convert it into a connectivity value? I find the beta values in the first level analysis folder in the matrix need "Z". But which of all these values should look at?
I plan to add more Seeds/sources in time. Do I need to change anything in the settings if I do so??
Attached file is the first level analysis results for one subject.
Thank you very much for your time,
BR