Dear SPM users,
I have some question about creation of sot.mat. First i would like to
share those which i understand. Then i am going to ask my question.
The given sot.mat file in the
web had 4 column and one row at first. then each column has 26 rows(
N1& N2 for non-familiar and F1 & F2 -for familiar faces).
Since it has 26 faces for each group that's why sot.mat matrix had 26 rows
and for N1,N2,F1& F2 , it had 4 column.
sot.mat file contain the
stimulus onset times, i.e.- it contain the information when the stimuli
has been given. As the information provided in the web, after showing one
face for 0.5 sec it gives a interval of 4 sec. After that it showed
another face for 0.5 sec. so obviously the
time interval between the two consecutive showing face is at least 5 sec.
But when i load the sot. mat file in the matlab and open the sot cell, i
found that there are some time interval
between the consecutive stimuli is 2.25 sec. I am attaching the
screen-print. Please check the attach file.
Question
: 1) Why the time interval is 2.25 sec?Question : 2) The picture is shown for 0.5 sec then in analysis time why we put duration (0) ? [ref: SPM5 manual.page 213( on the step of Modeling categorical responses)
#yiv622742031 {margin:0in;margin-bottom:.0001pt;font-size:12.0pt;font-family:"Times New Roman";}
_filtered #yiv622742031 {margin:1.0in 1.25in 1.0in 1.25in;}
#yiv622742031 div.Section1
{}
-->
Question : 3) In
case of the following experiment what should be the stimuli time difference? Is the answer [12 24 36 48…..] and the duration [1]? Please verify my answer.
Experiment : Subjects were instructed to perform a
key-press with both index fingers every time they saw the word tap appear on the
screen. The stimulus appeared every 12 sec and remained on the screen for 1
sec. In the interim, subjects were instructed to fixate on a white cross-hair
in the middle of the screen. There were 24 trials in a 5-min block.
question 4) what should be number of rows and columns (according to the experiment state above) in the sot.mat file?
question 5) From where i could learn more about content of the sot.mat file?
N:B- I am working in a third world country where no one ever heard about the software SPM. That's why no one is going to help me anymore. I learned everything by reading on the web and different journal. So please me to create the sot.mat file. I know how to make this .mat file on matlab but confused about the content of that file.please help.
Best regards,
Tanvir
