Hi Freesurferers
Could you please let me know how I should calculate the high pass filter cutoff? I have seen a bunch of different formulas (i.e 1.5*the stimulation period)? My task is a block-designed task, each stimuli takes 16 seconds and is followed by the next stimuli without an ITI. TR=2, number of conditions=8. I have used a hpf=0.01, Is this correct?
Thanks Mona
There is not a hard and fast formula. With a block length of 16 sec, you will have frequencies at 0.0625Hz and multiples thereof. The closer you are to 0.625, the more signal you are going to lose. Also, if you don't remove the whitening, then FSFAST will compute a highpass filter for you. I think that .01Hz is probably fine, but you could bump it up to .02Hz too
On 8/6/2020 6:11 PM, Nasiriavanaki, Zahra wrote:
Hi Freesurferers
Could you please let me know how I should calculate the high pass filter cutoff? I have seen a bunch of different formulas (i.e 1.5*the stimulation period)? My task is a block-designed task, each stimuli takes 16 seconds and is followed by the next stimuli without an ITI. TR=2, number of conditions=8. I have used a hpf=0.01, Is this correct?
Thanks Mona
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Hi Doug
Thanks so much for your reply. This is a question that a reviewer has pointed out. They were concerned that with the stimuli duration of 16 sec, maybe I am not using the correct hpf cutoff. Could you please refer me a paper about this?
Thanks Mona
On Aug 7, 2020, at 10:15 AM, Douglas N. Greve dgreve@mgh.harvard.edu wrote:
There is not a hard and fast formula. With a block length of 16 sec, you will have frequencies at 0.0625Hz and multiples thereof. The closer you are to 0.625, the more signal you are going to lose. Also, if you don't remove the whitening, then FSFAST will compute a highpass filter for you. I think that .01Hz is probably fine, but you could bump it up to .02Hz too
On 8/6/2020 6:11 PM, Nasiriavanaki, Zahra wrote:
Hi Freesurferers
Could you please let me know how I should calculate the high pass filter cutoff? I have seen a bunch of different formulas (i.e 1.5*the stimulation period)? My task is a block-designed task, each stimuli takes 16 seconds and is followed by the next stimuli without an ITI. TR=2, number of conditions=8. I have used a hpf=0.01, Is this correct?
Thanks Mona
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Sorry, I don't have a paper on it
On 8/7/2020 10:27 AM, Nasiriavanaki, Zahra wrote:
Hi Doug
Thanks so much for your reply. This is a question that a reviewer has pointed out. They were concerned that with the stimuli duration of 16 sec, maybe I am not using the correct hpf cutoff. Could you please refer me a paper about this?
Thanks Mona
On Aug 7, 2020, at 10:15 AM, Douglas N. Greve dgreve@mgh.harvard.edu wrote:
There is not a hard and fast formula. With a block length of 16 sec, you will have frequencies at 0.0625Hz and multiples thereof. The closer you are to 0.625, the more signal you are going to lose. Also, if you don't remove the whitening, then FSFAST will compute a highpass filter for you. I think that .01Hz is probably fine, but you could bump it up to .02Hz too
On 8/6/2020 6:11 PM, Nasiriavanaki, Zahra wrote:
Hi Freesurferers
Could you please let me know how I should calculate the high pass filter cutoff? I have seen a bunch of different formulas (i.e 1.5*the stimulation period)? My task is a block-designed task, each stimuli takes 16 seconds and is followed by the next stimuli without an ITI. TR=2, number of conditions=8. I have used a hpf=0.01, Is this correct?
Thanks Mona
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Could you please explain how you came up with “0.0625 Hz”? You mentioned in your first email: “With a block length of 16 sec, you will have frequencies at 0.0625Hz and multiples thereof.”
Thanks Mona
On Aug 7, 2020, at 10:42 AM, Douglas N. Greve dgreve@mgh.harvard.edu wrote:
Sorry, I don't have a paper on it
On 8/7/2020 10:27 AM, Nasiriavanaki, Zahra wrote:
Hi Doug
Thanks so much for your reply. This is a question that a reviewer has pointed out. They were concerned that with the stimuli duration of 16 sec, maybe I am not using the correct hpf cutoff. Could you please refer me a paper about this?
Thanks Mona
On Aug 7, 2020, at 10:15 AM, Douglas N. Greve dgreve@mgh.harvard.edu wrote:
There is not a hard and fast formula. With a block length of 16 sec, you will have frequencies at 0.0625Hz and multiples thereof. The closer you are to 0.625, the more signal you are going to lose. Also, if you don't remove the whitening, then FSFAST will compute a highpass filter for you. I think that .01Hz is probably fine, but you could bump it up to .02Hz too
On 8/6/2020 6:11 PM, Nasiriavanaki, Zahra wrote:
Hi Freesurferers
Could you please let me know how I should calculate the high pass filter cutoff? I have seen a bunch of different formulas (i.e 1.5*the stimulation period)? My task is a block-designed task, each stimuli takes 16 seconds and is followed by the next stimuli without an ITI. TR=2, number of conditions=8. I have used a hpf=0.01, Is this correct?
Thanks Mona
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Oh, Sorry, it chould probably have been .0313Hz. Assuming that it is 16 sec on and 16 sec off, then the period is 32 sec. 1/32sec = .0313Hz
On 8/7/2020 11:29 AM, Nasiriavanaki, Zahra wrote:
Could you please explain how you came up with “0.0625 Hz”? You mentioned in your first email: “With a block length of 16 sec, you will have frequencies at 0.0625Hz and multiples thereof.”
Thanks Mona
On Aug 7, 2020, at 10:42 AM, Douglas N. Greve dgreve@mgh.harvard.edu wrote:
Sorry, I don't have a paper on it
On 8/7/2020 10:27 AM, Nasiriavanaki, Zahra wrote:
Hi Doug
Thanks so much for your reply. This is a question that a reviewer has pointed out. They were concerned that with the stimuli duration of 16 sec, maybe I am not using the correct hpf cutoff. Could you please refer me a paper about this?
Thanks Mona
On Aug 7, 2020, at 10:15 AM, Douglas N. Greve dgreve@mgh.harvard.edu wrote:
There is not a hard and fast formula. With a block length of 16 sec, you will have frequencies at 0.0625Hz and multiples thereof. The closer you are to 0.625, the more signal you are going to lose. Also, if you don't remove the whitening, then FSFAST will compute a highpass filter for you. I think that .01Hz is probably fine, but you could bump it up to .02Hz too
On 8/6/2020 6:11 PM, Nasiriavanaki, Zahra wrote:
Hi Freesurferers
Could you please let me know how I should calculate the high pass filter cutoff? I have seen a bunch of different formulas (i.e 1.5*the stimulation period)? My task is a block-designed task, each stimuli takes 16 seconds and is followed by the next stimuli without an ITI. TR=2, number of conditions=8. I have used a hpf=0.01, Is this correct?
Thanks Mona
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
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