Creation of a SPM.mat file:
1) Create Notepad file for groups - Assign one group 0 and one group 1 - For each subject in the first group assign a 0 and the second group's subjects should be assigned a 1
2) Open SPM using the PET and SPECT option
3) Go to Matlab terminal and type x=load('path to directory with Notepad file with group assignments')
4) Enter
5) Back in SPM click Basic Models
6) Select Two sample t-test
7) Select all 1st group images and all 2nd group images
8) Done
9) When prompted type x
10) Enter
11) Select no grand mean scaling
12) Threshold masking: None
Choices: None, absolute, relative
13) "Implicit Mask (ignore 0's)?" Choose YES
14) "Explicitly Mask Images?" Choose yes or no depending on use of mask
15) Global Calculation None or omit
16) Save resulting image as .jpg or .pdf
Analysis:
1) In SPM press Estimate
2) Locate and select SPM.mat (this file was created in the process above - if this file was not saved in the directory you originally wanted this can be changed in SPM by clicking Utils and selecting cd and choosing your new directory)
3) Press Results
4) Select SPM.mat
5) Click t-contrasts
6) Define new contrasts at bottom of window
7) Title your analysis
8) Select t-contrast
9) In box type either 1 -1 0 or -1 1 0 depending on your group order
[i.e. If dyslexics are loaded 1st, -1 1 0 corresponds to Controls > Dyslexics]
10) Mask with other contrasts: No
11) Type in title
12) Enter
13) P-value adjustment select default
* Default = NONE; Choices: None, FWE, FDR
14) Select the default choice for the rest of the options
* Threshold (T or P Value) = 0.001
* Extent Threshold (voxels) = 0
15) Once page shows up in bottom left hand window click cluster under p-values - this should provide you with a table of clusters and their p-values
It is also possible to choose FWE and FDR t-test analysis on SPM
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