Dear Gabor,
Hello. I discuss this in this paper:
"Investigating hemodynamic response variability at the group level
using basis functions"
NeuroImage
Volume 49, Issue 3, 1 February 2010, Pages 2113-2122
Rik Henson also discusses this in his paper which I discuss.
Jason
On Mon, Feb 20, 2012 at 2:44 AM, Mark Jenkinson <[log in to unmask]> wrote:
> Hi,
>
> There's no simple answer to this question.
> The approximation gets progressively worse as the shift increases, and it depends on the
> TR as to how quickly it gets "bad". It will also depend on what your design is like as to how
> important the approximation errors are.
>
> It is normally quite reasonable to expect it to compensate for the majority of the differences
> in timing (due to slice timings and variations in the HRF) with a TR of 2-3 seconds.
>
> If you really want to quantify the accuracy more, then you can simulate some delays and
> run FEAT with a temporal derivative to see how well it compensates for these with your
> specific TR and design.
>
> All the best,
> Mark
>
>
>
>
> On 19 Feb 2012, at 18:44, Gabor Perlaki wrote:
>
>> Hi all,
>>
>> I've read in several articles that temporal derivative can compensate for a "small" temporal shift between the simulated and the actual Bold-responses. But, how much is the maximum temporal shift which can be compensated by this way? Could anybody help me in this issue?
>>
>> Thanks, Gabor
>>
|