Hi Christopher,
What I meant was how should one design the experiments to so that activations in the visual cortex can be minimised, or conversely so that activations in the motor cortex can be more easily observed? For example, are audio cues a better idea? Or using a block design with non-uniform intervals??
Thanks again.
Louis.
On Mon, 17 Jun 2013 11:30:50 -0400, Chris Watson <[log in to unmask]> wrote:
>Why do you call it an "unintended effect"? Visual cortex activation is
>inevitable here.
>Did that patient move a lot? There seems to be motion artifact.
>I don't think it is symmetrical, at least looking at the first 3 in the
>bottom row (and a couple before that).
>
>
>On 06/17/2013 11:14 AM, Louis Shue wrote:
>> Hi Andreas
>>
>> On Mon, 17 Jun 2013 12:49:59 +0200, Andreas Bartsch <[log in to unmask]> wrote:
>>
>>> Hi,
>>>
>>> if the subjects >sees< a cue and has to attend to it to get the on and
>>> off, you expect visual activations, don't you?
>> This is exactly what I was afraid might be the case but, since we were not involved in the experimental design, I was wondering how might one isolate this unintended effect during the experimental design? And is there anything that can be done to suppress visual cortex activations without introducing additional artifacts?
>>
>> >From what I can see there is also left M1 activation. Was the ball put
>>> into the right hand?
>> Yes the ball was in the right hand. Pardon my ignorance but how did you see the "left M1 activation"? From what I can tell from rendered_thresh_zstat1.png the activations were more or less symmetrical?
>>
>> Louis.
>>
>>> Cheers,
>>> Andreas
>>>
>>> Am 17.06.13 12:45 schrieb "Louis Shue" unter <[log in to unmask]>:
>>>
>>>> Dear FSL experts,
>>>>
>>>> We are currently using FEAT (so far only first level analysis) to analyse
>>>> some fMRI recordings as a part of study on stroke rehabilitation. The
>>>> experimental protocol seems "conventional" enough from what I can gather
>>> >from literature.
>>>> The subject (both controls and stroke patients) sees a prompt at set
>>>> intervals. When it's 'on', in our case the subject squeezes and releases
>>>> a pressure ball continuously, using the same hand for a given recording
>>>> session). When it's 'off' the subject relaxes. There are 5 'on' cycles in
>>>> each session.
>>>>
>>>> However, the results from FEAT show very strong activations in the visual
>>>> cortex region, instead in the motor cortex!? I am not sure if we are
>>>> doing anything wrong here, but can someone suggest how we may
>>>> isolate/enhance the desired effects somehow?
>>>>
>>>> I have included the raw data and the model file - in 3 column format - if
>>>> anyone wants to take a look. In the model file, it's initially in the
>>>> 'off' state, all measures in seconds.
>>>>
>>>> Any advice is greatly appreciated!
>>>>
>>>> data (for a control subject, performing the required action using the
>>>> right hand) :
>>>>
>>>> https://dl.dropboxusercontent.com/u/8460189/Cn001_20110902_CIRC_Irvin_007_
>>>> ep2d_bold_3.nii.gz
>>>> https://dl.dropboxusercontent.com/u/8460189/bold3_active_right.txt
>>>>
>>>> (part of) FEAT output:
>>>>
>>>> https://dl.dropboxusercontent.com/u/8460189/rendered_thresh_zstat1.png
>>>> https://dl.dropboxusercontent.com/u/8460189/tsplot_zstat1.png
>>>>
>>>> TR=3, High pass cutoff=100, BET brain extraction checked.
>>>>
>>>> Cheers,
>>>> Louis.
>>
>
>
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