# [Eeglablist] 回复：Re: Re: How to get same time points of different epoch in the function newtimef?

methodlearning at sina.cn methodlearning at sina.cn
Wed Apr 1 20:22:55 PDT 2015

```Dear Makoto,

Thank you !

When the value of “End Time-(window
length)/2-Start Time+(window length)/2” can be divisible by “timesout”, the
calculation method of time points output sounds clearly.

But if the value cannot be divisible by “timesout”,
how newtimef determined the times point output?

e.g.

1.      250ms
window length

2.      from
-1000ms to 2000ms epoch length

3.      200
timesout

The calculation method is not  “round”/’Ceil”
or “floor” according to my own experience. When the value can’t be divisible, the
time interval of adjacent time points seems not to be fixed.

I.P.----- 原始邮件 -----

Dear anonymous friend,
The superficial temporal resolution is determined in this way.
If1000ms window length (i.e. half of its length will be removed from the both ends of the epoch length)from -1000ms to 2000ms epoch length
200 timesoutthen you'll see -500ms to 1500ms divided by 200 == 10 ms time resolution in the output plot. If you want to have the same output, you need to feed the same length of the data, which should be possible.
See slide 21 of this pdfhttp://sccn.ucsd.edu/mediawiki/images/1/19/C2_A3_Time-frequencyDecAndAdvancedICAPracticum.pdf

Makoto

On Tue, Mar 31, 2015 at 2:40 AM,  <methodlearning at sina.cn> wrote:
Hi Makoto,Thanks a lot for your reply!If I use the function newtimef to decompose epochs of different
conditions and give input parameter "timesout" the same value, the
time points output after 0 ms will be very different across conditions because
the time spans were different .For example,
if I decompose different epochs using the same function newtimef(EEG.data(elec,:,:)EEG.pnts,[EEG.xmin
EEG.xmax]*1000,500,’cycles’,[2 0.5],'baseline',BaselineVector,'timesout',250,'nfreqs',93,'winsize',250),the
time points output after 0 ms for condition A will be :[6 14 20 26 34 40 46 52
60 66 72 80 86 92...];and condition B :[4 12 22 30 38 46 54 62 72
80 ...];and condition C:[4 10 16 22 28 34 40
46...].However, I need to compare ersp value across conditions on the same
time points using ANOVA after decomposing. The decomposing results of condition
A mentioned above included the ersp data at the time point"6", and
results of condition B and C didn't include the time point"6",so we
can't do ANOAV. And I am not interested in the ersp value before 0 ms . So I need to know how to get ersp value on one-one corresponding time
points after 0 ms across conditions of different epoch span.Maybe I need to know newtimef algorithm
of determining time points output ,to adjust the input parameter
"timesout", to get ersp value on one-one corresponding time points
across conditions(after 0 ms) .I am not sure if I made myself clear now?Thank you again for your help!

I.P.----- 原始邮件 -----

Dear I.P.,
Makoto
M
On Sat, Mar 28, 2015 at 10:34 PM,  <methodlearning at sina.cn> wrote:
Hi all,      In the time-frequency analysis,the epoch methods of different conditions were different:The epoch of condition A was [-1400 800]ms,and the baseline was [-1300 -1000]ms;The epoch of condition B was [-1832 800]ms ,and the baseline was[-1732 -1432]ms;The epoch of condition C was [-1220 800]ms ,and the baseline was[-1120 -820]ms;   I am not interested in the  decomposition results before 0 ms,but I need to compare above conditions on the time points after 0 ms.I did this using the function newtimef,but the output time points of conditions were so different that I can't compare these conditions .How can I get same time points after 0 ms of different epoch?Thank you ! I am very appreciated your answers!                                                                                                                              I.P.
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--
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego

--
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego

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