The cut-off is based on the expected frequency of your data. For most event-related designs, 128 should be fine as you don't have any low frequencies below (1/128s) in your design. For block designs, where the data tends to more period, you want to increase the number (decrease the frequency) to make it at least twice as long as your block to block of the same condition interval.

Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
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On Wed, Jul 1, 2015 at 2:42 AM, David Pascucci <[log in to unmask]> wrote:

Thanks Donald, and is the same cutoff optimal if I define a unique event of interest on each trial and the five conditions with a single parametric modulator?
Best

Il mercoledì 1 luglio 2015, MCLAREN, Donald <[log in to unmask]> ha scritto:

The default 128Hz should be fine as the conditions are randomly mixed.

Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
=====================
This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED
HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED and which is
intended only for the use of the individual or entity named above. If the
reader of the e-mail is not the intended recipient or the employee or agent
responsible for delivering it to the intended recipient, you are hereby
notified that you are in possession of confidential and privileged
information. Any unauthorized use, disclosure, copying or the taking of any
action in reliance on the contents of this information is strictly
prohibited and may be unlawful. If you have received this e-mail
unintentionally, please immediately notify the sender via telephone at (773)
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On Tue, Jun 30, 2015 at 5:49 PM, David <[log in to unmask]> wrote:

Dear SPMers,
if I have a fast event-related design with 5 conditions of interest randomly intermixed across trials, with each trial lasting 6.6 secs (3 tr) and the onset of each condition placed ~5secs after the beginning of a trial, what is the best cutoff for the high pass filter at the 1st level analysis?

--

Pascucci David

__________________________________________
Department of Neurological and Movement Sciences
Section of Physiology and Psychology, University of Verona
Strada Le Grazie 8, I-37134 Verona, Italy