# Same Localization Error for sLORETA and eLORETA despite different SNR - Seeking Explanation

**URL:** <https://mne.discourse.group/t/same-localization-error-for-sloreta-and-eloreta-despite-different-snr-seeking-explanation/8632>\
**Category:** Support & Discussions\
**Tags:** source-localization\
**Created:** [April 12, 2024, 11:22am UTC](https://mne.discourse.group/t/same-localization-error-for-sloreta-and-eloreta-despite-different-snr-seeking-explanation/8632 "2024-04-12T11:22:20Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![SMMB](https://avatars.discourse-cdn.com/v4/letter/s/ad7895/32.png) [@SMMB](https://mne.discourse.group/u/SMMB)\
**Post date:** [April 12, 2024, 11:22am UTC](https://mne.discourse.group/t/same-localization-error-for-sloreta-and-eloreta-despite-different-snr-seeking-explanation/8632/1 "2024-04-12T11:22:20Z")

</div>

During a source estimation exercise using the MNE-Python package, the localization error (which is calculated using Euclidean distances between the pairs of ground truth and estimated locations) was found to be exactly the same for both sLORETA and eLORETA, despite using different SNR. Can you explain why this might be the case?

Parameters:  
n\_dipoles = 1000  
duration = 2  
random\_state = 3

Compute inverse operator  
loose = 0.2  
depth = 0.8  
SNR = 3

- MNE version: e.g. 1.6.1
- operating system: macOS 14

---

<div class="post-metadata">

**Author:** ![wmvanvliet](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/wmvanvliet/32/100_2.png) [@wmvanvliet](https://mne.discourse.group/u/wmvanvliet)\
**Post date:** [April 15, 2024, 1:45pm UTC](https://mne.discourse.group/t/same-localization-error-for-sloreta-and-eloreta-despite-different-snr-seeking-explanation/8632/2 "2024-04-15T13:45:51Z")

</div>

if the noise you are adding is zero-mean white noise, then the estimated source location is likely still correct even when adding a little more noise. This is why in simulation studies, you should add some noise with a more interesting covariance structure, for example the noise covariance from our sample dataset.

---

<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\
**Post date:** [April 22, 2024, 1:46pm UTC](https://mne.discourse.group/t/same-localization-error-for-sloreta-and-eloreta-despite-different-snr-seeking-explanation/8632/3 "2024-04-22T13:46:05Z")

</div>

Closed on April 22, 2024, 1:46pm UTC

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.