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<p style="margin-top:0;margin-bottom:0">Let me be more specific/clear:</p>
<p style="margin-top:0;margin-bottom:0">I'm analyzing data from a patient with an ECOG. I want to compare the power-spectrum of the electrodes and the MEG cortical labels I've created around each electrode. </p>
<p style="margin-top:0;margin-bottom:0">It seems that calculating the time series in the source space of long enough MEG epochs (~10s), split the electrodes file to same length epochs, and use </p>
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<div>mne.time_frequency.psd_array_multitaper on both of them is the way to go, and also I know that both are in the same units (10*log10 for [dB]).</div>
<div>But I'm still a little bit confused by the different results I'm getting when using <span>mne.minimum_norm.compute_source_psd_epochs instead.</span></div>
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<div><span>Thanks,</span></div>
<div><span>Noam</span></div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> mne_analysis-bounces@nmr.mgh.harvard.edu <mne_analysis-bounces@nmr.mgh.harvard.edu> on behalf of Peled, Noam <NPELED@mgh.harvard.edu><br>
<b>Sent:</b> Wednesday, August 29, 2018 2:32:39 PM<br>
<b>To:</b> mne_analysis@nmr.mgh.harvard.edu<br>
<b>Subject:</b> [Mne_analysis] Cortical labels power spectrum different approaches</font>
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<p style="margin-top:0; margin-bottom:0">Hey all,</p>
<p style="margin-top:0; margin-bottom:0">I'm calculating MEG cortical labels power spectrum (for resting state data) in two different ways. Can you help me understand the differences? The power spectrums are quite different (see attached). <br>
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1) Go through the source space time-series:</p>
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<div>stcs = mne.minimum_norm.apply_inverse_epochs(epochs, ...)</div>
<div>labels_ts = mne.extract_label_time_course(stcs, labels, ...)</div>
<div>for label_ts:</div>
<div> psds, freqs = mne.time_frequency.psd_array_welch(label_ts, ...)</div>
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<div> psds = 10 * np.log10(psds)</div>
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2) Compute the PSD from the epochs:</p>
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<div>for label_ind, label in enumerate(labels):</div>
<div> stcs = mne.minimum_norm.compute_source_psd_epochs(epochs, ...)</div>
<div> for stc in stcs:</div>
<div> psds = np.mean(stc.data, axis=0)</div>
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Thanks!</p>
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Noam</p>
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