Dear Vladimir,
Thank you for you reply. I have an additional question if you don't mind.
Would it also be possible to construct model families where i use a
single effect but with different contraints on how the connections
change over trials. e.g.
family 1: -1 0 0 1
family 2: -2 -1 1 2
family 3: -1 -1 1 1
etc...
thanks in advance.
Frederik
Citeren Vladimir Litvak <[log in to unmask]>:
> Dear Frederik,
>
> These two ways are equivalent, just you don't need the first row in the
> first way as your first condition will be your baseline and the differences
> will be defined relative to it. So:
>
> 0 1 0 0
> 0 0 1 0
> 0 0 0 1
>
> Whether to prefer the first or the second way, depends on how you want to
> interpret the results. For instance, if you thing that the two main effects
> should affect different connections then it would make sense to use the
> second way.
>
> Best,
>
> Vladimir
>
>
> On Mon, Dec 14, 2015 at 1:01 PM, Frederik Van de Steen <
> [log in to unmask]> wrote:
>
>> Dear DCM experts,
>>
>> I have two questions regarding the design for ERP's when using DCM. If i
>> have a factorial design (2 x 2) what is the best way to set up the design?
>> e.g. include 4 effects:
>> 1 0 0 0
>> 0 1 0 0
>> 0 0 1 0
>> 0 0 0 1
>>
>> or 3 and than something like
>>
>> -1 1 0 0
>> -1 0 1 0
>> -1 0 0 1
>>
>> cheers
>>
>> Frederik
>>
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