Not muchHi doug,Thanks doug.Here are two questions that I am not sure:1, Each stimulus condition has three elements, i.e. cue fixation and picture. However it is only picture element that will be analyzed. The time window of picture will not influence the efficiency of sequence?
You can create a minimum fixed amount of after the trial with --tnullmin2, After stimulus presented(last 1.5s), subjects will response to the picture in the specific time window. This time window followed the stimulus, and it varied from 2.5s to ~8.5s. However, some trials was not followed by NULL trial. That is to say, there is no time to response after some trials.
ThanksAll the bestRujing Zha2014-06-20
charujing123
发 件人：Douglas Greve <greve@nmr.mgh.harvard.edu>发 送时间：2014-06-20 21:18主 题：Re: [Freesurfer] some questions about optseq收 件人："freesurfer"<freesurfer@nmr.mgh.harvard.edu>抄 送：
I don't think there is anything wrong with what you have. Is there a problem? You could shorten it to something like 240sec or so.
On 6/20/14 1:43 PM, charujing123 wrote:Hi doug,Thanks doug.In our experiment, there are 324s, and TR=2s, two kinds of stimulus. Each one consisted of 3 components(cue 500ms + fixation 500ms + picture 500ms), and will be presented with a interval of 1.5s. After stimulus onset, followed by reaction time. One stimulus will repeat 41 times, the other 40 times.Based on optseq2 --ntp 162 --tr 2 --psdwin 0 20 --ev ev1 2 40 --ev ev2 2 40 --nkeep 2 --o ex2 --nsearch 1000, how should I modify to get a efficient sequence, as I have no idea about NULL design.Thanks againAll the bestRujing Zha2014-06-20
charujing123
发 件人：Douglas Greve <greve@nmr.mgh.harvard.edu>发 送时间：2014-06-20 16:51主 题：Re: [Freesurfer] some questions about optseq收 件人："freesurfer"<freesurfer@nmr.mgh.harvard.edu>抄 送：
I don't understand what you are trying to do. Can you elaborate? There is no way to make optseq produce a sequence where two events always occur in a certain order
On 6/20/14 4:27 AM, charujing123 wrote:
.22 and 11 is the same condition(this condition has 40 repeats); 12 and 21 is the same condition(this condition also has 40 repeats). That is to say, there are two conditons in this run. 81 trials in this run, and each trial has 1.5s intervels. And mean intertrial intervals is 3.5s. Our TR is 2s.According the efficiency about these two conditions, how could I design the intertrial intervals to get a appropriate sequence?I tried this:optseq2 --ntp 203 --tr 2 --psdwin 0 20 --ev ev1 2 40 --ev ev2 2 40 --nkeep 2 --o ex2 --nsearch 1000Although it echo a result, I know, it is not what I need, because of every condition having two trials. So how I complete that?Thanks.All the best.Rujing Zha2014-06-20
charujing123
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