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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-family:"Times New Roman","serif";color:#1F497D'>Dear EEGLAB experts,<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'>(1) Is it true that ICA must be subject, like all the model-based spectral analysis methods, to a recommendation that one decimate to the lowest frequency capable of representing the actual signal content of the data without alienation effects? <b>Does one <u>NEED</u> to decimate the data before running ICA?</b> For instance, we have a data set recorded at 1,000 Hz. Do we need to decimate this to approximately 128 or 256?<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'>(2 ) According to the formula that Dr. Makeig gave to determine the optimal amount of data, <b>#timepoints/(#channels)^2</b>, it would appear that a <b>higher sampling rate will give better ICA results</b>. Is this the case?<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'>(3) Finally, using this formula, <b>#timepoints/(#channels)^2</b>, is there a <b>threshold or cutoff</b> one needs to be exceeded to have the optimal amount of data to run ICA. Simply doing the equation without any way to interpret the output is not helpful.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'>Thanks for your help,<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'>Dr. Modestino<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D;mso-fareast-language:EN-US'>Edward Justin Modestino, Ph.D.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D;mso-fareast-language:EN-US'>Postdoctoral Research Associate<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D;mso-fareast-language:EN-US'>Ray Westphal Neuroimaging Laboratory<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D;mso-fareast-language:EN-US'>Division of Perceptual Studies<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D;mso-fareast-language:EN-US'>Department of Psychiatry and Neurobehavioral Sciences <o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D;mso-fareast-language:EN-US'>University of Virginia<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Times New Roman","serif";color:#1F497D;mso-fareast-language:EN-US'>Email: ejm9f@virginia.edu<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><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></body></html>