<div dir="ltr">Thanks. I will use second one.<br><br>With regard ERNiftiDataset: does this class may somehow help to analyze the ER designs (specifically fast ER), where the data is extremely contaminated with previous BOLD signal?<br>
<br><div class="gmail_quote">2009/4/29 Yaroslav Halchenko <span dir="ltr"><<a href="mailto:debian@onerussian.com">debian@onerussian.com</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
there are a few options you have...<br>
<br>
in a block design experiment you can either<br>
1. discard volumes on the boundaries of the blocks -- look at<br>
idsonboundaries<br>
method of a dataset to figure out which volumes you need to discard<br>
<br>
2. shift labels to account for šthe hemodynamic response... lets say<br>
with TR=2 and desired shift of 6 seconds, just shift labels by 3 and<br>
discard first 3 volumes... smth like (just typed in... not tested ;))<br>
<br>
dataset.labels[3:] = dataset.labels[:-3]<br>
dataset = dataset.selectSamples(range(3, dataset.nsamples))<br>
<br>
3. use BoxcarMapper mapper to just get a mean activation pattern of the<br>
block (or simply use that ERNiftiDataset in the fashion similar to<br>
ER-dataset analysis)<br>
<div class="im"><br>
<br>
<br>
On Wed, 29 Apr 2009, Vadim Axel wrote:<br>
<br>
> š šHi guys,<br>
> š šI wonder whether you are making hemodynamic lag shift in pyMVPA? Here<br>
> š šit the thread, where you discussed this issue with regard to Haxby's<br>
> š šdataset.<br>
</div>> š š[1]<a href="http://www.mail-archive.com/pkg-exppsy-pymvpa@lists.alioth.debian.or" target="_blank">http://www.mail-archive.com/pkg-exppsy-pymvpa@lists.alioth.debian.or</a><br>
<div class="im">> š šg/msg00173.html<br>
> š šI think it's a critical procedure, especially when designed consists of<br>
> š šshort blocks (like 10-15 secs), where you might miss considerable<br>
> š šamount of information. As far as I remember in Princeton MVPA matlab<br>
> š štoolbox such a option existed.<br>
> š šThaanks,<br>
> š šVadim<br>
<br>
</div>> óÓÙÌËÉ<br>
<div class="im"><br>
> š š1. <a href="http://www.mail-archive.com/pkg-exppsy-pymvpa@lists.alioth.debian.org/msg00173.html" target="_blank">http://www.mail-archive.com/pkg-exppsy-pymvpa@lists.alioth.debian.org/msg00173.html</a><br>
<br>
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<br>
<br>
--<br>
Yaroslav Halchenko<br>
Research Assistant, Psychology Department, Rutgers-Newark<br>
Student šPh.D. @ CS Dept. NJIT<br>
Office: (973) 353-1412 | FWD: 82823 | Fax: (973) 353-1171<br>
š š š š101 Warren Str, Smith Hall, Rm 4-105, Newark NJ 07102<br>
WWW: š š <a href="http://www.linkedin.com/in/yarik" target="_blank">http://www.linkedin.com/in/yarik</a><br>
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</blockquote></div><br></div>