[FieldTrip] DICS beamformer images

[jan-mathijs schoffelen]

Hi Holly,

DICS can also be used to compute univariate power in a given frequency band. This yields not a bounded quantity. Depending on your analysis settings you will observe a depth bias which is not physiologically relevant. Best way to deal with this is to compute the beamformer maps using an experimental contrast.

Best

Jan-Mathijs

On Dec 6, 2011, at 2:18 PM, Rossiter, Holly wrote:

> Hi all,
>  
> I am using DICS to assess coherence and viewing the beamformer images through SPM. What I want to know is what is the value given in the image and how is it calculated? I thought it was a coherence value but it is not bounded between 0 and 1.
>  
> Also what do you think is the best way to threshold the images in order to get rid of low value peaks?
>  
> Thanks,
>  
> Holly
>  
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Jan-Mathijs Schoffelen, MD PhD 

Donders Institute for Brain, Cognition and Behaviour, 
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands

Max Planck Institute for Psycholinguistics,
Nijmegen, The Netherlands

J.Schoffelen at donders.ru.nl
Telephone: +31-24-3614793

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