Hello everyone,
I am having some trouble with block averaging and I’m not sure if I fully understand it correctly.
I am currently working on a task that includes 12 blocks with 11 rest periods in between. There are 3 different block types, each separated by rest periods. The experiment structure is something like this:
t1 – rest – t1 – rest – t2 – rest – t2 – rest – t3 – rest – t3 – rest – t3 – rest – t3 – rest – t2 – rest – t2 – rest – t3 – rest – t3
Each block lasts 30 seconds, and I have triggers marking the start and end of every block. However, some of my triggers overlap. I also made a mistake in one part of the data where I incorrectly labeled a trigger (I sent “A:222” instead of “A:223” for a single event).
Since I have 3 task types, I should only be averaging the blocks corresponding to each type. I recorded the data using the Artinis Brite system and I am analyzing it with Homer3 (v1.87.0, MATLAB R2017b, Windows 11).
The issue is that even after removing the incorrect trigger, the number of trials for t3 still appears as 5 instead of 4. Am I misunderstanding how nTrials is computed, or could there be another issue causing this?
Any help would be greatly appreciated. Thank you in advance!
Hi @ssanli ,
In Homer3, you only need a trigger at the beginning of each block, so you should remove the triggers marking the end of the blocks.
Also, in the sequence you provided, I count 6 blocks of t3, but you mentioned expecting 4 trials. Could you clarify this discrepancy?
Best,
Meryem
Oh, I am sorry I wrote wrong. Last 2 should be t1. All task types repeat 4 times. Like this:
t1 – rest – t1 – rest – t2 – rest – t2 – rest – t3 – rest – t3 – rest – t3 – rest – t3 – rest – t2 – rest – t2 – rest – t1 – rest – t1
English