<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear Chris,<div><br></div><div>yes, this is fine. There is a simpler and more elegant way. You only have 4 channels and EEGLAB will not plot power scalp maps if you have less than 5 channels. Add an extra channel and plot the scalp map in a given time-frequency range (18 22 Hz and 100 to 200 ms for instance). Then you can just collect the numbers and export them (no need to select specific frequencies or time range).</div><div><br></div><div>Hope this helps,</div><div><br></div><div>Arno</div><div><br><div><div>On Oct 7, 2010, at 6:48 AM, Christopher Retzler wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>
<div><font face="Arial" color="#000000" size="2"><p class="MsoNormal" style="MARGIN: 0cm 0cm 10pt"><font face="Calibri" size="3">I am currently analysing ERSP data from a concurrent choice task and wondered if the following approach is OK?</font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 10pt"><font size="3"><font face="Calibri"><span style="mso-spacerun: yes"> </span>I pre-calculate the Frequency measures and then use the following code to create variables containing the ERSP data:</font></font></p><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">STUDY<span style="mso-spacerun: yes"> </span>= pop_erspparams(STUDY, ‘freqrange’, [0 35]);<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">[STUDY erspdata ersptimes erspfreqs] = std_erspplot(STUDY, ALLEEG, ‘channels’, {‘E5’, ‘E6’,’E11’, ‘E12’}, ‘plotsubjects’, ‘on’);<span style="mso-spacerun: yes"> </span>% Frontal cluster of electrodes<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'"><o:p> </o:p></span></div><p class="MsoNormal" style="MARGIN: 0cm 0cm 10pt"><font face="Calibri" size="3">I then extract the data for each subject in each condition for the frequency of interest (in this case beta) and the relevant time period:</font></p><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">Fz_choc = erspdata{1,2}(25:54,107:136, 1, 1);<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">Fz_cigs = erspdata{1,2}(25:54,107:136, 1, 1);<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'"><o:p> </o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="mso-bidi-font-family: 'Courier New'"><font size="3"><font face="Calibri">I then calculate the mean beta power for each subject and condition. This data can then be exported to SPSS for ANOVA analysis along with other behavioural variables etc. Is it OK to average the data in this way?<o:p></o:p></font></font></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="mso-bidi-font-family: 'Courier New'"><o:p><font face="Calibri" size="3"> </font></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="mso-bidi-font-family: 'Courier New'"><font size="3"><font face="Calibri">Thanks in advance.<o:p></o:p></font></font></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="mso-bidi-font-family: 'Courier New'"><o:p><font face="Calibri" size="3"> </font></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-bottom: 0pt; margin-left: 0cm; "><span style="mso-bidi-font-family: 'Courier New'"><font size="3"><font face="Calibri">Chris<o:p></o:p></font></font></span></div></font></div><br><p>
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