<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Karl,<div><br></div><div>This is perfectly fine behavior.</div><div><br></div><div>ft_connectivityanalysis either outputs a 'chan_chan_freq' matrix, or a 'chancmb_freq' matrix. The former will be the output when the input freq-structure contains fourier-spectra, and the cfg lacks a channelcmb field. Ft_connectivityanalysis then computes connectivity between all channel pairs, which can conveniently be stored in a square matrix 'chan_chan' for each frequency. If the freq-structure contains cross-spectra (and power-spectra), or if you specify a cfg.channelcmb in combination with fourierspectra in the input, you will get the connectivity data to be 'chancmb_freq', i.e. each row in the matrix contains a spectrum. The reason for this is that it is a priori unlikely that the channelcmb-array defines a set of channel pairs that can be represented in a square all-to-all matrix. If it is your intention to end up with a square matrix, you may want to consider first doing a subselection of channels, i.e. computing your fourierspectra only on the subset of channels you want to use in a later step, and then call ft_connectivityanalysis without a channelcmb field in the cfg.</div><div><br></div><div>See for some additional information about the different representation of frequency domain data: <a href="http://fieldtrip.fcdonders.nl/faq/in_what_way_can_frequency_domain_data_be_represented_in_fieldtrip">http://fieldtrip.fcdonders.nl/faq/in_what_way_can_frequency_domain_data_be_represented_in_fieldtrip</a></div><div><br></div><div>Cheers,</div><div><br></div><div>Jan-Mathijs</div><div><br></div><div><br></div><div><br><div><div>On Feb 18, 2012, at 2:16 AM, Karl Doron wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div class="gmail_quote">Hello,<div><br></div><div>I'm trying to run ft_connectivityanalysis on a reduced set of MEG channels, i.e., left and right posterior channels. Because neighboring channels are highly correlated, I'd like to exclude them and look only at "inter-hemispheric" connections.</div>
<div><br></div><div>I'm having some troubling getting ft_channelcombination to produce this set of channels. I have 43 channels per hemisphere giving n(n-1)/2 connections. I made an NX2 matrix using repmat.m and passed it as cfg.channelcmb; however the output of ft_connectivityanalysis gave a vector for 'cohspctrm' rather than a chan_chan_freq matrix.</div>
<div><br></div><div>Thanks for any suggestions.</div><span class="HOEnZb"><font color="#888888"><div><br></div><div>Karl Doron</div><div>UC Santa Barbara</div>
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<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Jan-Mathijs Schoffelen, MD PhD </div><div><br></div><div>Donders Institute for Brain, Cognition and Behaviour, <br>Centre for Cognitive Neuroimaging,<br>Radboud University Nijmegen, The Netherlands</div><div><br></div><div>Max Planck Institute for Psycholinguistics,</div><div>Nijmegen, The Netherlands</div><div><br></div><div><a href="mailto:J.Schoffelen@donders.ru.nl">J.Schoffelen@donders.ru.nl</a></div><div>Telephone: +31-24-3614793</div></div></span></div></span></div></span></div></span></div></span></span>
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