Hi Pierre,

I was recently asked a question about the length of temporal block (h) that has to be determined to replicate data using CBB.

What is suggested from BASC is h=the square root of the total number of time points (T) in each run, in order to preserve the temporal structure in the resting-state fMRI time-series.
 
So if T=200, h can be randomly selected between 10 and 30, for example.

Assuming another case, when T=500, for example, h is now becoming larger.

The question was, for the "resting state" data, shouldn't a desired level of the temporal structure be the same for any T? 
So why not using a temporal block of h=square root of 200 for data with T=500?

What is the best answer for this question?

Best,
Kangjoo