<meta http-equiv="Content-Type" content="text/html; charset=utf-8"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><br><code><span class="gmail-c1"><font face="arial,helvetica,sans-serif">
</font></span></code><p class="MsoNormal" style="margin-bottom:12pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">Hi everyone,</span></p>
<p class="MsoNormal" style="margin-bottom:12pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">I am a
newbie in Fieldtrip and I'm trying to do a cluster-based permutation test
within subjects. I am looking at these two tutorials:<br>
<a href="http://www.fieldtriptoolbox.org/tutorial/cluster_permutation_timelock/">http://www.fieldtriptoolbox.org/tutorial/cluster_permutation_timelock/</a><br>
<a href="http://www.fieldtriptoolbox.org/tutorial/eventrelatedstatistics/">http://www.fieldtriptoolbox.org/tutorial/eventrelatedstatistics/</a></span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">In the two
of them, it is said that the steps to follow are (in order):
ft_timelockanalysis, ft_timelockgrandaverage, and ft_timelockstatistics.</span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">However, in
<a href="http://www.fieldtriptoolbox.org/tutorial/cluster_permutation_timelock/">http://www.fieldtriptoolbox.org/tutorial/cluster_permutation_timelock/</a> they
seem to perform ft_timelockanalysis followed by ft_timelockstatistics and after
that, they do ft_timelockgrandaverage (this is not what is proposed in the
other tutorial). I don't know if this makes a big difference or not, but inconsistencies
across tutorials are confusing. Moreover, in the within-subjects part (<a href="http://www.fieldtriptoolbox.org/tutorial/cluster_permutation_timelock/">http://www.fieldtriptoolbox.org/tutorial/cluster_permutation_timelock/</a>),
it is said that the configuration in neighbours creation is the same as in the
between-trials:</span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB"> </span></p>
<p class="MsoNormal" style="margin-bottom:12pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">“cfg.neighbours
= neighbours;<span> </span>% same as defined for the
between-trials experiment”</span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">Nevertheless,
in the between-trials experiment, they use the GA_FC to do the neighbours
structure, but in the within-subjects trial it is not possible to do so,
because the grandaverage is only done after the permutation test. So what we
need to do?</span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">In sum, my
questions are:</span></p>
<p class="gmail-MsoListParagraphCxSpFirst" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB"><span>1.<span style="font:7pt "Times New Roman"">
</span></span></span><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">When does one need to do the grandaverage?</span></p>
<p class="gmail-MsoListParagraphCxSpLast" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB"><span>2.<span style="font:7pt "Times New Roman"">
</span></span></span><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">If the grandaverage is done after the permutation
analysis, what do we write in the neighbours’ structure? The output from
ft_timelockanalysis (i.e. allsubjFC)?</span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB"> </span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">Thanks in
advance,</span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB"> </span></p>
<p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal"><span style="font-size:12pt;font-family:"Times New Roman",serif" lang="EN-GB">Iris</span></p>
<div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><span><b>Iris Milán Maillo</b><br>
<br>
PhD Student<br><a href="https://www.upf.edu/web/spb" target="_blank">Speech Production and Bilingualism (SPB)</a><br>
<a href="http://cbc.upf.edu/cbc.upf.edu/" target="_blank">Center for Brain and Cognition (CBC)</a><br>
<br>
Carrer de Ramon Trias Fargas, 25-27, 08005 Barcelona | Edifici Merce Rodoreda, (room 24.311)<br>
</span></div></div></div></div></div></div></div></div></div></div></div>