[FieldTrip] beamformer

[Arjen Stolk]

Hi Ye Mei,

Source-reconstructed activity (using the beamformer method) typically has a
depth-bias (see van Veen et al., IEEE '97). Taking the relative
increase/decrease of activity from baseline (effectively implementing a
normalization per grid point location) is less prone to this bias as
compared to taking the absolute difference. Hope this answers your question,

Arjen


2013/7/3 Frank Mei <frank.ye.mei at gmail.com>

> Hello FieldtripList,
>
> In the beamformer tutorial (
> http://fieldtrip.fcdonders.nl/tutorial/beamformer), the contrast of
> (post-pre)/pre was calculated. I am wondering why can't one just
> calculate (post-pre), instead.
>
> Could someone explain that?
>
> thanks,
> Ye Mei
>
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