[Homer-users] Cutoff value to remove high frequency noise

[Meryem Ayse Yucel]

Hi Hue,

This value is chosen to remove heart beat (which is ~1Hz, test this by
looking at your data for hearbeat with and without lpf) and instrumental
noise available in the data. You can use lower values, but that has the
risk of removing the hemodynamic response itself.

Meryem


> Dear all,
>
> I would like to ask about the cutoff value to remove high frequency noise
> in fNIRS data.
>
> In recent papers (Brigadoi et al (2014) Motion artifacts in functional
> near-infrared spectroscopy A comparison of motion correction techniques
> applied to real cognitive data, Yucel (2014) Targeted principle component
> analysis - a new motion artifact correction approach for near-infrared
> spectroscopy, ...) the authors used 0.5 Hz as cutoff value for the lowpass
> filter and there was no reference or explanation about that value.
>
> I do not understand why 0.5 was chosen. Could you help me on this?
>
> Thank you very much in advance for your response.
>
> Kind regards,
> Hue.
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