<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear Zuyue,<div><br></div><div>I agree with Eelke. One thing you need to check is whether the time axis (in data.time{}) is in seconds or milliseconds.</div><div>In the cfg to ft_freqanalysis you specify it in seconds. FieldTrip does not care about the exact units, so you need to ensure that the units in the time-axis correspond.</div><div><br></div><div>BW,</div><div><br></div><div>Jan-Mathijs</div><div> <br><div><div>On Dec 16, 2011, at 1:44 PM, Eelke Spaak wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Dear Zuyue,<br><br>When you invoke ft_singleplotTFR, do you specify a means of baseline<br>correction and/or explicit z-limits (i.e., limits of the color axis)?<br>When looking at raw power (i.e., not contrasted), it is advisable to<br>use a baseline correction in order to see something. Also, specifying<br>z-limits of a different order of magnitude than your data will of<br>course lead to all blue plots.<br><br>You should take a look at the time-frequency analysis tutorial,<br>particularly the part about visualization:<br><a href="http://fieldtrip.fcdonders.nl/tutorial/timefrequencyanalysis#visualization">http://fieldtrip.fcdonders.nl/tutorial/timefrequencyanalysis#visualization</a><br><br>If you still don't see anything after you use baseline correction (or<br>plot a contrast instead) and have proper z-limits, there might be<br>something else wrong.<br><br>Best,<br>Eelke<br><br>2011/12/16 chenzuyue <chenzuyue@live.cn>:<br><blockquote type="cite">Hi, everyone,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I am a new user of FieldTrip. In my study, I want to computes the difference<br></blockquote><blockquote type="cite">of time-frequency representations of event-related LFP in two conditions.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">The data in the first condition is a 4 X 1100 X 103 matrix (Nchan X Nsamples<br></blockquote><blockquote type="cite">X Ntrials). The data in the second condition is a 4 X 1100 X 107 matrix. The<br></blockquote><blockquote type="cite">data reformatted are as follows:<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dataset1.label (4 X 1 cell );<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dataset1.fsample 1000;<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dataset1.trial (1 X 103 cell );<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dataset1.time (1X 103 cell); % time is from -100ms to 999ms.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dataset2.label (4 X 1 cell );<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dataset2.fsample 1000;<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dataset2.trial (1 X 107 cell );<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dataset2.time (1X 107 cell ); % time is from -100ms to 999ms.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">The frequency interested is 0-100Hz. The method to calculate TFRs is the<br></blockquote><blockquote type="cite">multitaper method. The configuration is as below:<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">cfg = [];<br></blockquote><blockquote type="cite">cfg.output = 'pow';<br></blockquote><blockquote type="cite">cfg.method = 'mtmconvol';<br></blockquote><blockquote type="cite">cfg.foi = 1:2:100;<br></blockquote><blockquote type="cite">cfg.t_ftimwin = 5./cfg.foi;<br></blockquote><blockquote type="cite">cfg.tapsmofrq = 0.4 *cfg.foi;<br></blockquote><blockquote type="cite">cfg.toi = -0.1:0.05:1;<br></blockquote><blockquote type="cite">cfg.pad = 'maxperlen';<br></blockquote><blockquote type="cite">TFRmult1 = ft_freqanalysis(cfg, dataset1);<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">But after running, I can not get the right results. When I use<br></blockquote><blockquote type="cite">ft_singleplotTFR to plot graph, there is only blue color. I wonder whether<br></blockquote><blockquote type="cite">the process and configuration is right.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">The method is from one paper of E Maris and R Oostenvels published on the<br></blockquote><blockquote type="cite">Journal of Neuroscience Methods.164(2007), 177-190; Figure 3.<br></blockquote><blockquote type="cite">http://www.ncbi.nlm.nih.gov/pubmed/17517438<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Any help is much appreciated.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Yours Sincerely,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Zuyue<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">_______________________________________________<br></blockquote><blockquote type="cite">fieldtrip mailing list<br></blockquote><blockquote type="cite">fieldtrip@donders.ru.nl<br></blockquote><blockquote type="cite">http://mailman.science.ru.nl/mailman/listinfo/fieldtrip<br></blockquote>_______________________________________________<br>fieldtrip mailing list<br>fieldtrip@donders.ru.nl<br>http://mailman.science.ru.nl/mailman/listinfo/fieldtrip<br></div></blockquote></div><br><div>
<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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