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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks Tim! <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>So, you are saying we should plot topomap before normalization using zscore for each channel…<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The reason behind my question is different subjects have different scalp and skull thickness which effects on the magnitude of EEG at electrode level. When one would want to do grand averaging over subjects this issue may cause a problem in averaging ( a subject with thinner scalp thickness has more share on the grand average data)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Any thought? <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Best,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Iman<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Tim Mullen [mailto:mullen.tim@gmail.com] <br><b>Sent:</b> Wednesday, November 07, 2012 11:10 PM<br><b>To:</b> Iman M.Rezazadeh<br><b>Cc:</b> Edward Justin Modestino; EEGLAB List<br><b>Subject:</b> Re: [Eeglablist] How to save the normalized data that we see in scroll data display?<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Yes, temporal z-normalization will generally change the voltage topography, since each electrode's mean voltage (DC offset) is removed and each electrode's voltage has been independently rescaled by a different quantity. <o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Note that we are not describing *spatial* z-normalization, which, for a given time point, is equivalent to performing a common average reference (subtracting spatial mean from each electrode) followed by rescaling all electrodes by the same quantity (spatial stdev). This will preserve relative voltage between pairs of electrodes within a constant factor (pairwise voltage difference is also rescaled by the spatial stdev) -- and, if data is already CAR, does not affect pairwise voltage ratios.<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>In any case, I can't see why one would want to temporally normalize before plotting voltage maps.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Tim<o:p></o:p></p></div></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p><div><p class=MsoNormal>On Wed, Nov 7, 2012 at 3:01 PM, Iman M.Rezazadeh <<a href="mailto:irezazadeh@ucdavis.edu" target="_blank">irezazadeh@ucdavis.edu</a>> wrote:<o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi,</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>So, I have one question here:</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If you normalize the data using zscore , then at each time point the topography of original data and normalized one will be different since for topo map the voltage of adjacent electrodes are also important? </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Could you please clarify more …</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Best,</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Iman</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Iman M.Rezazadeh, PhD</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Postdoctoral Research Fellow</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Center for Mind and Brain</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>University of California, Davis</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><a href="mailto:irezazadeh@ucdavis.edu" target="_blank">irezazadeh@ucdavis.edu</a></span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Cell:<a href="tel:310-490-1808" target="_blank">310-490-1808</a></span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Skype: Imanmr</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <a href="mailto:eeglablist-bounces@sccn.ucsd.edu" target="_blank">eeglablist-bounces@sccn.ucsd.edu</a> [mailto:<a href="mailto:eeglablist-bounces@sccn.ucsd.edu" target="_blank">eeglablist-bounces@sccn.ucsd.edu</a>] <b>On Behalf Of </b>Edward Justin Modestino<br><b>Sent:</b> Tuesday, November 06, 2012 6:50 AM<br><b>To:</b> Tim Mullen<br><b>Cc:</b> EEGLAB List<br><b>Subject:</b> Re: [Eeglablist] How to save the normalized data that we see in scroll data display?</span><o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'>Yes, this code works:<br><b>normdata = zscore(EEG.data,0,2);<br>EEG.data = normdata;</b><o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>On Mon, Nov 5, 2012 at 9:07 PM, Tim Mullen <<a href="mailto:mullen.tim@gmail.com" target="_blank">mullen.tim@gmail.com</a>> wrote:<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>As I posted earlier, <span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>it's simple to compute:</span><o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> </span><o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>normdata = zscore(EEG.data,0,2);</span><o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> </span><o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>No need to reshape, etc. This will normalize each channel and each epoch independently.</span><o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> </span><o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Tim</span><o:p></o:p></p></div></div><div><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'> <o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>On Fri, Nov 2, 2012 at 11:23 AM, Makoto Miyakoshi <<a href="mailto:mmiyakoshi@ucsd.edu" target="_blank">mmiyakoshi@ucsd.edu</a>> wrote:<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Dear Edward,<br><br>> Error: Expression or statement is incorrect--possibly unbalanced (, {, or [.<br><br>Oops. The line must be<o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><br>tmp = reshape(EEG.data, [size(EEG.data, 1) size(EEG.data, 2) *<o:p></o:p></p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>size(EEG.data, 3) ]);<br><br>The last parenthesis was missing.<br>By the way I learned a shortcut for it yesterday, and<br><br>tmp = EEG.data(:,:);<br><br>should also work.<br><br>Makoto<br><br><br>2012/11/2 Edward Justin Modestino <<a href="mailto:edward.modestino@gmail.com" target="_blank">edward.modestino@gmail.com</a>>:<br>> Makoto,<br>> I need to be able to get this working as well. I tried it and got the<br>> following error.<o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>><br>><br>>>> tmp = reshape(EEG.data, [size(EEG.data, 1) size(EEG.data, 2) *<br>> size(EEG.data, 3) ];<br>> tmp = zscore(tmp, 0, 2);<br>> tmp = reshape(tmp, size(EEG.data));<br>> EEG.data = tmp;<o:p></o:p></p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>> ??? tmp = reshape(EEG.data, [size(EEG.data, 1) size(EEG.data, 2) *<br>> |<br>> Error: Expression or statement is incorrect--possibly unbalanced (, {, or [.<o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>><br>><br>> On Thu, Nov 1, 2012 at 1:21 PM, Makoto Miyakoshi <<a href="mailto:mmiyakoshi@ucsd.edu" target="_blank">mmiyakoshi@ucsd.edu</a>><br>> wrote:<br>>><br>>> Dear nabaraj,<br>>><br>>> Check out the function zscore.<br>>> If your data are epoched, then the code should be something like<br>>><br>>> tmp = reshape(EEG.data, [size(EEG.data, 1) size(EEG.data, 2) *<br>>> size(EEG.data, 3) ];<br>>> tmp = zscore(tmp, 0, 2);<br>>> tmp = reshape(tmp, size(EEG.data));<br>>> EEG.data = tmp;<br>>><br>>> This should normalizes each channel.<br>>><br>>> Makoto<br>>><br>>> 2012/10/29 nabaraj dahal <<a href="mailto:nabarajdahal@gmail.com" target="_blank">nabarajdahal@gmail.com</a>>:<br>>> > Dear list member,<br>>> > I wish to save the normalized data of all channels for further<br>>> > processing.<br>>> > Is there any way I can save the normalized data of all channels that we<br>>> > see<br>>> > in scroll data display?<br>>> > I would be grateful for you help.<br>>> ><br>>> > Best Regards,<br>>> > Nab<br>>> ><br>>> > _______________________________________________<br>>> > Eeglablist page: <a href="http://sccn.ucsd.edu/eeglab/eeglabmail.html" target="_blank">http://sccn.ucsd.edu/eeglab/eeglabmail.html</a><br>>> > To unsubscribe, send an empty email to<br>>> > <a href="mailto:eeglablist-unsubscribe@sccn.ucsd.edu" target="_blank">eeglablist-unsubscribe@sccn.ucsd.edu</a><br>>> > For digest mode, send an email with the subject "set digest mime" to<br>>> > <a href="mailto:eeglablist-request@sccn.ucsd.edu" target="_blank">eeglablist-request@sccn.ucsd.edu</a><br>>><br>>><br>>><br>>> --<br>>> Makoto Miyakoshi<br>>> JSPS Postdoctral Fellow for Research Abroad<br>>> Swartz Center for Computational Neuroscience<br>>> Institute for Neural Computation, University of California San Diego<br>>> _______________________________________________<br>>> Eeglablist page: <a href="http://sccn.ucsd.edu/eeglab/eeglabmail.html" target="_blank">http://sccn.ucsd.edu/eeglab/eeglabmail.html</a><br>>> To unsubscribe, send an empty email to<br>>> <a href="mailto:eeglablist-unsubscribe@sccn.ucsd.edu" target="_blank">eeglablist-unsubscribe@sccn.ucsd.edu</a><br>>> For digest mode, send an email with the subject "set digest mime" to<br>>> <a href="mailto:eeglablist-request@sccn.ucsd.edu" target="_blank">eeglablist-request@sccn.ucsd.edu</a><br>><br>><br>><br><br><br>--<br>Makoto Miyakoshi<br>JSPS Postdoctral Fellow for Research Abroad<br>Swartz Center for Computational Neuroscience<br>Institute for Neural Computation, University of California San Diego<br>_______________________________________________<br>Eeglablist page: <a href="http://sccn.ucsd.edu/eeglab/eeglabmail.html" target="_blank">http://sccn.ucsd.edu/eeglab/eeglabmail.html</a><br>To unsubscribe, send an empty email to <a href="mailto:eeglablist-unsubscribe@sccn.ucsd.edu" target="_blank">eeglablist-unsubscribe@sccn.ucsd.edu</a><br>For digest mode, send an email with the subject "set digest mime" to <a href="mailto:eeglablist-request@sccn.ucsd.edu" target="_blank">eeglablist-request@sccn.ucsd.edu</a><o:p></o:p></p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><br><br clear=all><o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>-- <o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>--------- αντίληψη -----------<o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'><br><br clear=all><br>-- <br>Edward Justin Modestino, Ph.D.<br>Neuroscientist/Faculty<br>Atlantic University<o:p></o:p></p></div></div></div></div></div><p class=MsoNormal><br><br clear=all><o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal>-- <br>--------- αντίληψη -----------<o:p></o:p></p></div></div></body></html>