<html><head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear Chen,<div><br></div><div>The power spectrum returned in EEGLAB is in unit 10*log10(uV^2/Hz) - see spectopo function output and plot for example.</div><div><br></div><div>In Wikipedia you can read below "The number of decibels is ten times the logarithm to base 10 of the ratio of the two power quantities"</div><div><br></div><div><a href="http://en.wikipedia.org/wiki/Decibel">http://en.wikipedia.org/wiki/Decibel</a></div><div><br></div><div>So when you compute ERSP and compute the ratio between spectral power at a given time/frequency point and power in the baseline, then take the log10 times 10 (as above), so you actually compute power ratio in dB.</div><div><br></div><div>Hope this helps,</div><div><br></div><div>Arno</div><div><br><div><div>On Nov 22, 2013, at 4:56 AM, Emily Chen <<a href="mailto:emilychen2013@gmail.com">emilychen2013@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><div dir="ltr"><span style="font-family:arial,sans-serif;font-size:13px">Dear all,</span><div style="font-family:arial,sans-serif;font-size:13px">How can I converse the ERSP from dB to microvolts-squared, after the data have been convolved with wavelet?</div>
<div style="font-family:arial,sans-serif;font-size:13px">Many thanks!<br></div><div style="font-family:arial,sans-serif;font-size:13px"><br></div><div style="font-family:arial,sans-serif;font-size:13px">Sincerely,</div><div style="font-family:arial,sans-serif;font-size:13px">
Lihong Chen</div><div style="font-family:arial,sans-serif;font-size:13px">Graduate Student</div><div style="font-family:arial,sans-serif;font-size:13px">Chinese Academy of Sciences, Institute of Psychology</div><div style="font-family:arial,sans-serif;font-size:13px">
Lab for Vision and Attention</div></div>
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