# get\_peak mode=abs gives negative values

**URL:** <https://mne.discourse.group/t/get-peak-mode-abs-gives-negative-values/4993>\
**Category:** Support & Discussions\
**Tags:** evoked\
**Created:** [June 3, 2022, 1:12pm UTC](https://mne.discourse.group/t/get-peak-mode-abs-gives-negative-values/4993 "2022-06-03T13:12:18Z")\
**Posts on this page:** 1\
**Showing post:** 7

<div class="post-metadata">

**Author:** ![Evelyne\_Fraats](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/evelyne_fraats/32/1729_2.png) [@Evelyne\_Fraats](https://mne.discourse.group/u/Evelyne_Fraats)\
**Post date:** [June 3, 2022, 2:41pm UTC](https://mne.discourse.group/t/get-peak-mode-abs-gives-negative-values/4993/7 "2022-06-03T14:41:37Z")

</div>

Thankyou! I would expect, based on the image above, P1 peaks at 0.097 with a peak value of 1.8microV. So I am trying to find this value and not the trough (probaly going towards N1).  
If I run `mode=pos` I sometimes get a NaN indicating no pos values are found (not in many cases). For my N1 timewindow (130ms - 200ms, mode = neg) I do get a lot of NaN’s. It seem that my N1 is not really negative in my data. See example:  
 ![example_neg_n1](https://global.discourse-cdn.com/free1/uploads/mne/original/2X/8/868a9cdb3fc5650b979c1c1fdd4d843e15569e29.jpeg)

I do not know exacly why this is the case. I tried a longer baseline, but this did not had an effect. I did apply current source density conversion, so maybe this can explain? Otherwise my data is, unfortunately, noisy. Since I had this problem, I though having `mode=abs` will give me no NaN anymore, and more statistical power especially for my N1 component. However, `mode=abs` is not detecting the peaks I want. Maybe I can try sometime like this: [Can get\_peak function specify the maximum or minimum value? - #2 by richard](https://mne.discourse.group/t/can-get-peak-function-specify-the-maximum-or-minimum-value/2673/2)

---

_[View the full topic](https://mne.discourse.group/t/get-peak-mode-abs-gives-negative-values/4993)._