Hi AS,
I've been using TSNR myself recently. As you say, it's simply mean / SD over the images in a time series. This can be calculated at each voxel for each subject and session and then combined to give a "coverage map" for the group. The individual or group maps can be used as an alternative to implicit masking to set the spatial limits of your analysis.
I'm attaching two Matlab files that calculate TSNR. The function calc_tsnr.m makes individual TSNR images, either from a list of image files or from the files for each session specified by an SPM.mat file. The second script calculate_tsnr_script.m batches the process for a set of subjects. In this case it searches for images based on prefix, using all matching images in the directory. You'll need to modify it for your experiment. You could also adapt it so it uses an SPM.mat file.
I hope these help. These are my personal scripts, not published, so are provided as is. Use at your own risk and check results are sensible etc.
Best wishes,
Paul Wright
On Wed, 1 May 2013 11:40:25 +0100, AS T.N <[log in to unmask]> wrote:
>Hello,
>
>I know such a question may not be posted here but I know there are lots of fMRI experts.
>
>I need to calculate the Temporal SNR for my fmrI data series. I found a nice paper the explains it ( Murphy et al 2007). I did that by taking the whole mean of the signal from the data and divide it by its std. I am sure that I missing something and there are accurate way to do it. Can someone please tell me or guide me to how I do it correctly in a practical terms? Can SPM help me here ?
>
>Thanks
>
>AS
