Print

---

In other words the cutoff frequencies are defined in terms of numbers  
of TRs. So 0.01Hz is (1/0.01)/3=33.3 TRs.
I should also warn against using bandpass preprocessing on FMRI  
timeseries if you plan on then feeding them into FILM. The FILM  
autocorrelation modelling is not designed to work on bandpass data  
and so the stats will go awry.

Cheers, Mark.

----
Dr Mark Woolrich
EPSRC Advanced Research Fellow University Research Lecturer

Oxford University Centre for Functional MRI of the Brain (FMRIB),
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK.

Tel: (+44)1865-222782 Homepage: http://www.fmrib.ox.ac.uk/~woolrich




On 8 Mar 2007, at 12:59, Arun Bokde wrote:

> Hi,
>
> I would like to apply a bandpass filter to my fmri time series  
> data. I see
> that the command ip request that the cutoff frequencies be set in  
> number of
> volumes and not frequency.  I am not sure how this works.  I would  
> like to
> set a frequency of 0.01 Hz and 0.15 Hz for the bandpass filter.  My  
> data
> has a TR = 3 sec.
>
> Thank you in advance.
>
> Best wishes,
> Arun