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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'>Dear Karen,<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'>Comparing the BVA and Fieldtrip images it seems that the trials in BVA have been filtered using at least a high-pass filter. I can see from the BVA image that you have applied filters prior to averaging your trials. From the Fieldtrip code you’ve posted I cannot see any filtering applied. If you could find out what filters were applied to the trials in BVA and apply the same filters to the trials in FieldTrip using ft_preprocessing your results will most likely be the same.<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'>Best,<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'>Jim<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 style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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"'> fieldtrip-bounces@science.ru.nl [mailto:fieldtrip-bounces@science.ru.nl] <b>On Behalf Of </b>Karen Schuil<br><b>Sent:</b> maandag 17 juni 2013 13:56<br><b>To:</b> fieldtrip@science.ru.nl<br><b>Subject:</b> [FieldTrip] ERP average Brain Vision is different from ERP average FieldTrip<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Dear Fieldtrip Users,<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I have a BVA-Fieldtrip problem. The average ERPs of Brain Vision Analyser are different from the ERPS of FieldTrip. It seems that in Fieldtrip a slow negative drift is added and peaks are more/less pronounced than in BVA (attached is a picture of the two different plots). <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>An expert FieldTrip User and I could not find a solution for this problem. I hope one of you has a suggestion for this problem.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>The individual trial data was exported from BVA (version 2.02.5859) with the following settings:<o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>File extension: .seg<br>Write header file: yes<br>Write marker file: yes<br>Format: BINARY<br>Orientation: MULTIPLEXED<br>Line Delimiter: CRLF (PC style)<br>Binary format: 16-Bit signed integer format<br>Set resolution manually: no<br>Individually optimized resolution for each channel: yes<br>Convert to big-endian order: no<br>Export all channels: no<br>Export the following channels:<br>AF3 AF4 AF7 AF8 AFz C1 C2 C3 C4 C5 C6 CP1 CP2 CP3 CP4 CP5 <br>CP6 CPz Cz F1 F2 F3 F4 F5 F6 F7 F8 FC1 FC2 FC3 FC4 FC5 <br>FC6 FCz Fpz FT7 FT8 Fz Iz O1 O2 Oz P1 P10 P2 P3 P4 P5 <br>P6 P7 P8 P9 PO3 PO4 PO7 PO8 POz Pz T7 T8 TP7 TP8</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Created Using Component Version 2.0.2.5827</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>We used Matlab version 7.10.0 R2, and fieldtrip version 13-06-2013 (and tried a version from 2011).</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>The scripts we used are read_analyzer_data and </span><span style='font-family:"Arial","sans-serif"'>timelockanalysis. This is the code we used for calling the scripts:</span><o:p></o:p></p></div><div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>% read data into fieldtrip<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg = [];<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.inputfile = 'pp10_A';<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.triggercode = 'S 20';<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.triggertype = 'Stimulus';<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.prestim = 1.2;<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.poststim = 1.7;<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>pp10_l = read_analyzer_data(cfg);<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>% check: compute ERP<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>% <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg = [];<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>pp10_ERP = timelockanalysis(cfg, pp10_l);<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>%plot ERP<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg = [];<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.layout = 'elec1010.lay';<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.xlim = [-0.15 1.7];<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.ylim = [-12.25 12.25];<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>% cfg.baseline = 'yes';<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>% cfg.baselinetype = 'absolute';<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.showlabels = 'yes';<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>cfg.interactive = 'yes';<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>multiplotER(cfg, pp10_ERP);<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>I hope you can help! </span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Kind regards,</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Karen</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><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><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div></div></div></div></div></div></body></html>