<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">
Dear Alex,
<div class=""><br class="">
</div>
<div class="">Change your scaling to ‘maxabs’ (cfg.zlim = ‘maxabs’;) to get a better feel of the scaling of your data. Now you have a scaling from 0 to 1, which, given your data, gives you very saturated images. </div>
<div class=""><br class="">
</div>
<div class="">Also, I would argue using a relative baseline on a TFR of an ERP (or ERF) is risky as in theory, your baseline should be zero (you even explicitly try to impose that by performing a baseline correction when calculating the ERP). This means that
you are dividing your activation period by values close to zero. This will give you arbitrarily large values. An absolute baseline is preferred. </div>
<div class=""><br class="">
</div>
<div class="">Best,</div>
<div class=""><br class="">
</div>
<div class="">Jim</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
<div class="">
<div>
<blockquote type="cite" class="">
<div class="">On 1 Aug 2017, at 11:52, Alexander Mentink <<a href="mailto:amentink@chdr.nl" class="">amentink@chdr.nl</a>> wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div id="divtagdefaultwrapper" style="font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; font-size: 12pt; background-color: rgb(255, 255, 255); font-family: Calibri, Arial, Helvetica, sans-serif;" class="">
<div style="margin-top: 0px; margin-bottom: 0px;" class="">Hi Fieldtrip community,</div>
<div style="margin-top: 0px; margin-bottom: 0px;" class=""><br class="">
</div>
<div style="margin-top: 0px; margin-bottom: 0px;" class="">I am trying to analyse time frequency representations of electrical evoked potentials, but I am not getting any reliable results at all.</div>
<div style="margin-top: 0px; margin-bottom: 0px;" class=""><br class="">
</div>
<div style="margin-top: 0px; margin-bottom: 0px;" class="">Using hanning window (1-30 Hz) or (4-30 Hz), wavelet transform with absolute baselinetype and relative baselinetype gives me four totally different results (see link)</div>
<div style="margin-top: 0px; margin-bottom: 0px;" class=""><br class="">
</div>
<div style="margin-top: 0px; margin-bottom: 0px;" class=""><a href="http://tinyurl.com/y7nerh8v" id="LPlnk953677" class="">http://tinyurl.com/y7nerh8v</a><br class="">
<br class="">
</div>
<div style="margin-top: 0px; margin-bottom: 0px;" class="">The EEG data is defined 1000 ms pre stimulus and 1200 ms post stimulus, artifacts removed and preprocessed with baseline correction between 200 ms and 0 ms, bandpass filtered between 0.5 - 30 Hz and
referenced to earlobes. The timelocked analysis is attached to the dropbox link as well.</div>
<div style="margin-top: 0px; margin-bottom: 0px;" class=""><br class="">
</div>
<div style="margin-top: 0px; margin-bottom: 0px;" class=""><b class="">The code I use for hanning window is</b></div>
<div style="margin-top: 0px; margin-bottom: 0px;" class="">%%%%%%%%%%%%%%%%%%</div>
<p style="margin-top: 0px; margin-bottom: 0px;" class=""></p>
<div class="">cfg = [];<br class="">
cfg.output = 'pow';<br class="">
cfg.channel = 'Cz';<br class="">
cfg.method = 'mtmconvol'; <br class="">
cfg.taper = 'hanning'; <br class="">
cfg.foi = 1:0.025:30; % OR 4:0.025:30<br class="">
cfg.t_ftimwin = 3./cfg.foi; <br class="">
cfg.toi = -0.5:0.01:0.7; <br class="">
TFRwave = ft_freqanalysis(cfg, trialdata);<br class="">
<br class="">
</div>
<div class="">% Visualization<br class="">
cfg = [];<br class="">
cfg.baseline = [-0.5 -0.1]; <br class="">
cfg.baselinetype = 'absolute'; <br class="">
cfg.maskstyle = 'saturation';<br class="">
cfg.zlim = [0 1];<br class="">
cfg.showlabels = 'yes'; <br class="">
figure<br class="">
ft_singleplotTFR(cfg, TFRwave)</div>
<div class=""><span style="font-family: Calibri, Arial, Helvetica, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', NotoColorEmoji, 'Segoe UI Symbol', 'Android Emoji', EmojiSymbols; font-size: 16px;" class="">%%%%%%%%%%%%%%%%%%</span><br class="">
</div>
<div class=""><span style="font-family: Calibri, Arial, Helvetica, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', NotoColorEmoji, 'Segoe UI Symbol', 'Android Emoji', EmojiSymbols; font-size: 16px;" class=""><br class="">
</span></div>
<div class=""><b class="">And for wavelet transform is</b></div>
<div class=""><span style="font-family: Calibri, Arial, Helvetica, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', NotoColorEmoji, 'Segoe UI Symbol', 'Android Emoji', EmojiSymbols; font-size: 16px;" class="">%%%%%%%%%%%%%%%%%%</span><br class="">
</div>
<div class="">
<div class="">cfg = [];</div>
<div class="">cfg.channel = 'Cz';<span style="white-space: pre;" class=""> </span>
</div>
<div class="">cfg.method = 'wavelet'; </div>
<div class="">cfg.width = 7; </div>
<div class="">cfg.output = 'pow';<span style="white-space: pre;" class=""> </span>
</div>
<div class="">cfg.foi = 1:0.5:30;<span style="white-space: pre;" class="">
</span> </div>
<div class="">cfg.toi = -0.5:0.05:1;<span style="white-space: pre;" class="">
</span></div>
<div class="">TFRwave = ft_freqanalysis(cfg, trialdata);</div>
<div class=""><br class="">
</div>
<div class=""><span style="font-size: 12pt;" class="">cfg = [];</span><br class="">
</div>
<div class="">cfg.baseline = [-0.5 -0.1]; </div>
<div class="">cfg.baselinetype = 'relative'; % OR absolute</div>
<div class="">cfg.maskstyle = 'saturation';<span style="white-space: pre;" class="">
</span></div>
<div class="">cfg.zlim = [0 1];<span style="white-space: pre;" class=""> </span>
</div>
<div class="">cfg.channel = 'Cz';</div>
<div class=""><span style="font-size: 12pt;" class="">figure</span><br class="">
</div>
<div class="">ft_singleplotTFR(cfg, TFRwave);</div>
<span style="font-family: Calibri, Arial, Helvetica, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', NotoColorEmoji, 'Segoe UI Symbol', 'Android Emoji', EmojiSymbols; font-size: 16px;" class="">%%%%%%%%%%%%%%%%%%</span><br class="">
</div>
<div class=""><span style="font-family: Calibri, Arial, Helvetica, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', NotoColorEmoji, 'Segoe UI Symbol', 'Android Emoji', EmojiSymbols; font-size: 16px;" class=""><br class="">
</span></div>
<div class="">I have tried the tutorials online, but this doesn't give me any better results...</div>
<div class=""><br class="">
</div>
<div class="">Does anyone know what I am doing wrong?</div>
<div class=""><br class="">
</div>
<div class="">Thanks many times!</div>
<div class=""><br class="">
</div>
<div class="">Best regards,</div>
<div class=""><br class="">
</div>
<div class="">Alex (Master student </div>
<br class="">
<p style="margin-top: 0px; margin-bottom: 0px;" class=""></p>
</div>
<br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">
<br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">
<table class="ImprintUniqueIDTable" cellspacing="0" cellpadding="0" border="0" style="margin: 0cm 0cm 0pt; font-family: Helvetica; letter-spacing: normal; orphans: auto; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; height: 254px; width: 432.375px; border-collapse: collapse;">
<tbody class="">
<tr class="">
<td style="width: 354px;" class=""><font face="Verdana" class=""><br class="">
</font><font style="font-family: Verdana; font-size: 12pt; font-weight: bold;" class="">Alexander Mentink</font> <br class="">
<font face="Verdana" class="">Centre for Human Drug Research<br class="">
Zernikedreef 8<br class="">
2333 CL Leiden<br class="">
The Netherlands</font><font style="font-family: Verdana; font-size: 12pt;" class=""><br class="">
T +31 (0) 71 7517166</font><br class="">
<font style="font-family: Verdana; font-size: 12pt;" class=""><a href="mailto:amentink@chdr.nl" class="">amentink@chdr.nl</a></font><br class="">
<font face="Verdana" class=""><a href="http://www.chdr.nl/" class="">http://www.chdr.nl</a><br class="">
<br class="">
Follow us:<span class="Apple-converted-space"> </span></font>
<table cellpadding="0" cellspacing="0" class="7567ec92-35cb-4269-b059-5b2b31db7757Table" style="font-family: Verdana; font-size: 12pt; text-align: left; vertical-align: top;">
<tbody class="">
<tr style="text-align: left; vertical-align: top;" class="">
<td align="Center" style="padding-right: 5px;" class=""><font style="font-family: Verdana; font-size: 12pt;" class=""><font style="font-family: Verdana; font-size: 12pt;" class=""><a href="http://www.twitter.com/chdr_nl" target="" class=""><span id="cid:imaged4db2c.PNG@2c41bb72.499acc90"><imaged4db2c.PNG></span></a></font></font></td>
<td align="Center" style="padding-right: 5px;" class=""><font style="font-family: Verdana; font-size: 12pt;" class=""><font style="font-family: Verdana; font-size: 12pt;" class=""><a href="http://www.linkedin.com/company/centre-for-human-drug-research" target="" class=""><span id="cid:imagecccaa4.PNG@b079db44.41ac4062"><imagecccaa4.PNG></span></a></font></font></td>
</tr>
</tbody>
</table>
<br class="">
<br class="">
</td>
</tr>
</tbody>
</table>
<br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">
<font face="Verdana" style="font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""></font><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">_______________________________________________</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">
<span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">fieldtrip
mailing list</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">
<a href="mailto:fieldtrip@donders.ru.nl" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class="">fieldtrip@donders.ru.nl</a><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">
<a href="https://mailman.science.ru.nl/mailman/listinfo/fieldtrip" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class="">https://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a></div>
</blockquote>
</div>
<br class="">
</div>
</body>
</html>