[Homer-users] Size of procResult.dcAvg

[anna at blasi.com]

Hi All, 

I have a question regarding the length (number of data samples) of the
averaged time course of the HRF stored in the *.nirs file after block
averaging the data. 

In Homer2 we have processed different data sets with multiple
participants each. We have defined a specific processing stream for each
one of the groups. In the processing stream we have defined the trange
for the block average, starting at 4 sec pre-stimulus onset to (task
duration + subsequent baseline), and we have processed (calculate HRF)
the data from all participants in a group using the "Group" option. 

Plot Probe plots the participant averaged blocks correctly, with the
plots showing the same block length as specified in the processing
stream. However, when loading the *.nirs files, we have noticed that
different participants have different block lengths as inspected by
size(procResult.dcAvg). 

Just to double check, we assume that the first N samples (N
corresponding to the block length) of procResult.dcAvg (per channel,
condition and chromophore) are those corresponding to the block as
defined in the processing stream. Correct? 

Also, why, for some participants, there are more samples stored even
though the block is defined in the processing stream? 

Many thanks! 

Anna 

 
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