Block design: BOLD response

AFNI Message Board
1

Hi, List experts,

I have a question in my mind for long time. If I want to do the ROI analysis for the fMRI data (say, block design experiment), can I also get the data point across time (i.e., 0-15s) as following example?

To illustration, when we let a person look at a stimulus, we will find a certain pattern of brain activation in the fusiform gyrus. At scan 1 the stimulus was presented; we can see that the BOLD response is sluggish, only 3 scans later (= 4.5 seconds) the activity reaches its peak. I know this is very common when we do the event-related design experiment. Does it meant that we can not get these kind of data points for block-design experiment?

Any comments are much appreciated.
J

2

If those blocks are largely separated from each other (e.g., 16 seconds apart), you might be able to extract the time series at a region after removing the confounding effects such as slow drift, head motion, etc.). Another possibility to model the BOLD response for each condition by using basis functions such as TENT/TENTzero, CSPLIN/CSPLINzero.

3

Thank you very much, Gang,

So it means that we can use TENT/TENTzero, CSPLIN/CSPLINzero for block designed datasets. I was wrongly thinking that we only can use them for the event-related design.

J