# Empty EEG values after Current source density transformation

**URL:** <https://mne.discourse.group/t/empty-eeg-values-after-current-source-density-transformation/5564>\
**Category:** Support & Discussions\
**Tags:** preprocessing, eeg, csd\
**Created:** [September 10, 2022, 12:55am UTC](https://mne.discourse.group/t/empty-eeg-values-after-current-source-density-transformation/5564 "2022-09-10T00:55:18Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![finch](https://avatars.discourse-cdn.com/v4/letter/f/51bf81/32.png) [@finch](https://mne.discourse.group/u/finch)\
**Post date:** [September 10, 2022, 12:55am UTC](https://mne.discourse.group/t/empty-eeg-values-after-current-source-density-transformation/5564/1 "2022-09-10T00:55:18Z")

</div>

I want to transform my EEG data with the Current source density transformation, and I followed the guide in [Transform EEG data using current source density (CSD) — MNE 1.1.1 documentation](https://mne.tools/stable/auto_examples/preprocessing/eeg_csd.html). Before the transformation, I removed 6 channels. And then plot the transformed data. However, no EEG values are plotted. The figure is empty. I do not know how to deal with this situation. Could you help me with this?

- MNE version: 1.1.1
- operating system: Windows 10

My code is as follows:

```python
%matplotlib inline
import os
import os.path as op
import mne
import numpy as np
import pandas as pd

examples_dir = r'F:\eeg\preprocess-byscript' # Path to the raw EEG Data folder 
sub_file = examples_dir+ r'\event_1.set' # Path to the raw EEG header file print(sub_file)

examples_dir = r'F:\eeg\preprocess-byscript' # Path to the raw EEG Data folder
sub_file = examples_dir+ r'\event_1.set' # Path to the raw EEG header file
print(sub_file)

raw = mne.io.read_raw_eeglab(sub_file) # Returns a Raw object containing BrainVision data
raw.load_data() # Loading continuous data

raw=raw.drop_channels(['CB1','CB2','VEO','HEO','M1','M2'])

raw_csd = mne.preprocessing.compute_current_source_density(raw)
raw.plot()
raw_csd.plot()

```

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