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<span style="font-family: Arial, Helvetica, sans-serif; font-size: small">Dear Fieldtrip community,</span><br>
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<div>I have a question about connectivity analysis, specifically on granger causality. I am working on MEG data at source level (LCMV method), and I am interested in studying connectivity between 2 pre-defined ROIs in 2 experimental conditions. Specifically,
I would like to calculate both coherence and granger causality, keeping information on both frequency and time dimensions. </div>
<div>So, I run time-frequency analysis with sliding time windows of frequency-dependent length, and used this ouput for ft_connectivityanalysis (please see the code pasted below). I obtained time-frequency coherence values, and I would like to do the same for
granger causality (i.e., keeping time dimension), because the effect I am interested in is narrowed in time (and so running a mtmfft may not be optimal). </div>
<div>I am wondering, is it possible to run granger causality in the time-frequency domain? Otherwise, how can I restrict the analysis on a time-window of interest?</div>
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<div>Any help would be really appreciated!</div>
<div>Thanks in advance.</div>
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<div>Best,</div>
<div>Agnese</div>
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<div><font face="verdana, sans-serif">%time-freq analysis</font></div>
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<div><font face="verdana, sans-serif">cfg=[];<br>
cfg.output='fourier';<br>
cfg.channel=[area1 area2];<br>
cfg.method='mtmconvol';<br>
cfg.taper='dpss';<br>
cfg.keeptrials='yes';<br>
cfg.toi = -1:0.01:1;<br>
cfg.foi = [1:128];<br>
cfg.tapsmofrq=0.4*cfg.foi;</font></div>
<div><font face="verdana, sans-serif">cfg.t_ftimwin = 5./cfg.foi; <br>
tfr_A =ft_freqanalysis(cfg, data_A);<br>
tfr_B =ft_freqanalysis(cfg, data_B);</font></div>
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<div><font face="verdana, sans-serif">%coherence</font></div>
<div><font face="verdana, sans-serif">cfg=[];<br>
cfg.method = 'coh';<br>
coh_A = ft_connectivityanalysis(cfg, tfr_A);<br>
coh_B = ft_connectivityanalysis(cfg, tfr_B);<br>
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<div><font face="verdana, sans-serif">%granger</font></div>
<div><font face="verdana, sans-serif">cfg=[];<br>
cfg.method='granger';<br>
cfg.granger.sfmethod='<wbr>bivariate';<br>
grang_A = ft_connectivityanalysis(cfg, ?);<br>
grang_B = ft_connectivityanalysis(cfg, ?);</font></div>
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<div>--<br>
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<div><font color="#666666" face="tahoma, sans-serif">Agnese Zazio, PhD<br>
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<div><font color="#666666" face="tahoma, sans-serif">Cognitive Neuroscience Section,</font></div>
<div><font color="#666666" face="tahoma, sans-serif">IRCCS Centro San Giovanni di Dio Fatebenefratelli</font></div>
<div><font color="#666666" face="tahoma, sans-serif">Via Pilastroni 4, 25125 Brescia, Italy</font></div>
<div><font face="tahoma, sans-serif"><font color="#666666">Phone number: </font><span style="line-height: 18px; text-align: justify"><a style="color: rgb(34, 34, 34)"><font color="#666666">(+39) 0303501-596</font></a></span></font></div>
<div><font face="tahoma, sans-serif"><font color="#666666">Site: </font><u><a href="http://www.cognitiveneuroscience.it/" target="_blank" style="color: rgb(17, 85, 204)"><font color="#0000ff">http://www.<wbr>cognitiveneuroscience.it</font></a></u></font></div>
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<div><font face="tahoma, sans-serif"><span style="color: rgb(102, 102, 102)">E-mail: </span><u style="color: rgb(17, 85, 204)"><span style="color: rgb(12, 100, 192)"><a href="mailto:agnese.zazio@cognitiveneuroscience.it" target="_blank" style="color: rgb(17, 85, 204)">agnese.zazio@<wbr>cognitiveneuroscience.it</a></span></u></font>
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