# Block wise bad channels interpolation before ICA ?

**URL:** <https://mne.discourse.group/t/block-wise-bad-channels-interpolation-before-ica/8840>\
**Category:** Support & Discussions\
**Tags:** preprocessing, eeg\
**Created:** [May 21, 2024, 8:01pm UTC](https://mne.discourse.group/t/block-wise-bad-channels-interpolation-before-ica/8840 "2024-05-21T20:01:59Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Alagebra](https://avatars.discourse-cdn.com/v4/letter/a/a8b319/32.png) [@Alagebra](https://mne.discourse.group/u/Alagebra)\
**Post date:** [May 21, 2024, 8:01pm UTC](https://mne.discourse.group/t/block-wise-bad-channels-interpolation-before-ica/8840/1 "2024-05-21T20:01:59Z")

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Hi, all.

Suppose I have a 10-block experiment and corresponding EEG file. In certain blocks, maybe 2 or 3, some channels became bad for some mysterious reasons. Is it OK to interpolate the bad channels within that specific block and then concatenate the whole ten blocks to create a longer file and run ICA with the longer file ?

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**Author:** ![mscheltienne](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/mscheltienne/32/827_2.png) [@mscheltienne](https://mne.discourse.group/u/mscheltienne)\
**Post date:** [May 23, 2024, 8:25am UTC](https://mne.discourse.group/t/block-wise-bad-channels-interpolation-before-ica/8840/2 "2024-05-23T08:25:29Z")

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That should be fine, as long as the number of components is below the minimum rank of your data.

Mathieu