Hi to all.
I want to create and estimate an fMRI model in SPM8. I have whole BOLD/EPI images acquired on a 1.5T Sigma Scanner(General Electric).
Each acquisition consists of 22 contiguos slices(3mmX3mmX3mm) with a TR of 3 sec.
I have already made images pre-processing(realignment, normalization, smoothing,...).
441 acquisitions were made in blocks(on + off) of 21 scans, so I have 21 blocks of 21 scans.
In each block(on + off) , I have 7 activation scans and 14 rest scans.
I have three types of activations, presented in pseudo-random sequence, so I have 7 blocks for each condition I want test.
The three conditions are electrical stimulations at different intensity.
For example :
off(14 scans) - condition1(7 scans) - off(14 scans) - condition3(7 scans) - off(14 scans) - condition1(7 scans) - off(14 scans) - condition2(7 scans) .....
and so on.
I want to obtain activation map for each condition, so condition1 vs. rest, condition2 vs. rest, condition3 vs. rest.
I have performed 1-st level analysis, but I haven't any activation for each condition.
Belove, I desccribe parameters I have used for model specification :
TIMING PARAMETERS :
- Units for design : SCAN;
- Interscan interval : 3 sec;
- Microtime resolution : 16;
- Microtime onset : 1;
DATA & DESIGN :
- Scans( all the 441 scans) ;
- Onset( the scan at which the condition start)
- Duration : 7;
- High Pass Filter : 84 ;
I have leaved all the other parameters set to default value.
N.B. I have tried to consider only scans corresponding to the conditions I want to test(so 147 scans for each conditions), but I have obtained any result.
Can anyone help me ?
Thank you.
