# Is it valid to eastimate the PSI (phase\_slope\_index) for single trial?

**URL:** <https://mne.discourse.group/t/is-it-valid-to-eastimate-the-psi-phase-slope-index-for-single-trial/5622>\
**Category:** Support & Discussions\
**Tags:** connectivity\
**Created:** [September 23, 2022, 9:51am UTC](https://mne.discourse.group/t/is-it-valid-to-eastimate-the-psi-phase-slope-index-for-single-trial/5622 "2022-09-23T09:51:13Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![YuZhou](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/yuzhou/32/76_2.png) [@YuZhou](https://mne.discourse.group/u/YuZhou)\
**Post date:** [September 23, 2022, 9:51am UTC](https://mne.discourse.group/t/is-it-valid-to-eastimate-the-psi-phase-slope-index-for-single-trial/5622/1 "2022-09-23T09:51:13Z")

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- MNE version: 1.1.1
- operating system: Linux

Hi! all,  
I noticed that in the output of the `mne_connectivity.phase_slope_index`, the dimension of epochs disappeared. So I manually make the input data as one epoch for each phase\_slope\_index estimation. I’m wondering if this operation is appropriate or valid. Or the PSI estimation is better to use more trials?