Dear all,
I am sorry that these are acrually quite amateurish questions. However, I stiil need some clarification of some of these terms and some other practical issues.
I am using SIEMENS trio 3T scanner in our data acquisition. My questions are as follows:
1) If I divide my entire scanning time series into multiple scan runs, there will be more than 1 GLMs (I suppose multiple sessions, as in lst level modelling in SPM, correspond to only multiple GLMs with a mutually independent set of onsets and durations for each one.) Thus, for each GLM, the implicit baseline will be different from others. So how can I combine the contrasts for these GLMs for group level analysis?
2) The second question is a more practical one. My entire scanning length is approximately 40mins. The motive for dividing scanning session into multiple runs is to avoid signal decay problem, after scanning for a long time. However, what I am not sure is whether it is necessary in my experiment? Has anybody used SIEMENS trio 3T scanner under similar circumstance?
Any advice and comments will be greatly appreciated.
Best regards,
Ce
