TSNR (Temporal Signal to Noise Ratio)ΒΆ
Influenced by the magnetic field inhomogeneity at air-tissue interfaces, rs-fMRI signals at orbitofrontal and temporal medial and polar areas suffer from a certain degree of distortions and signal loss. To exclude spurious voxels, we use the thresholded voxel-wise TSNR, which is calculated as the average intensity of time series divided ty the standard deviation, to generate subject-level or group-leval whole-brain mask.
- mask: could be whole brain mask or gray matter mask.
- id index: identifier to find unique string for each subject
- filetype: files in the filetype will be searched in input directories.
- 4D nifti files: if the input data is 4D, check this item. Otherwise uncheck.
- input dirs: directories can be input either using a
*.txt
file or spm select window. - threshold: intensity threshold for mean TSNR (to generate a binary mask).
- out dir: output directory for saving results.
- Buttons:
- S: Save parameters of the current panel to a
*.mat
file. The*.mat
can be further loaded for the panel or be used in a script processing. - L: Load parameters from
*.mat
for the current panel. - ?: Help information.
- S: Save parameters of the current panel to a
- References:
- Tomasi D, Volkow ND. Functional connectivity density mapping. Proceedings of the National Academy of Sciences of the United States of America 2010; 107(21): 9885-90.
- Yeo BT, Krienen FM, Sepulcre J, Sabuncu MR, Lashkari D, Hollinshead M, et al. The organization of the human cerebral cortex estimated by intrinsic functional connectivity. J Neurophysiol 2011; 106(3): 1125-65.
- Welvaert M, Rosseel Y. On the definition of signal-to-noise ratio and contrast-to-noise ratio for FMRI data. PLoS One 2013; 8(11): e77089.