# Problems understanding events from annotations

**URL:** <https://mne.discourse.group/t/problems-understanding-events-from-annotations/7229>\
**Category:** Support & Discussions\
**Tags:** epochs\
**Created:** [July 12, 2023, 8:09pm UTC](https://mne.discourse.group/t/problems-understanding-events-from-annotations/7229 "2023-07-12T20:09:03Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![LEPacheco](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/lepacheco/32/2833_2.png) [@LEPacheco](https://mne.discourse.group/u/LEPacheco)\
**Post date:** [July 12, 2023, 8:09pm UTC](https://mne.discourse.group/t/problems-understanding-events-from-annotations/7229/1 "2023-07-12T20:09:03Z")

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- MNE version: 1.4.2
- MNE-connectivity version: 0.5.0
- operating system: Windows 10
- Python version: 3.11.4

I’m trying to calculate connectivity between 9 sensors but I’m getting trouble understanding the concept of chunk duration and events in the method _**mne.events\_from\_annotatins()**_  
I want to analyze the signal in 1s epochs, but I have two versions of the code, as it is shown below, with different output values.  
The first one is indicating **chunk duration = 1** ,  
The second one, the raw signal is the only parameter.

```python
event_1s_chunk = mne.events_from_annotations(raw, chunk_duration=1)
#event_1s = mne.events_from_annotations(raw) #Second option
epoc_1s_chunk = mne.Epochs(canales, event_1s_chunk[0], tmin=0, tmax=1, baseline=None)

```

I’m new to EEG - Connectivity topics, but to the best of my knowledge, setting _epochs_ is the window of analysis and they would fit in my _1s chunk duration_. So if I don’t indicate _chunk duration_, wouldn’t it be the same?

Hope I’m getting explained and someone can help me

---

<div class="post-metadata">

**Author:** ![scott-huberty](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/scott-huberty/32/2715_2.png) [@scott-huberty](https://mne.discourse.group/u/scott-huberty)\
**Post date:** [July 12, 2023, 11:08pm UTC](https://mne.discourse.group/t/problems-understanding-events-from-annotations/7229/2 "2023-07-12T23:08:23Z")

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Hi @LEPacheco

If I’m understanding correctly, and you just want to create 1-second epochs from your raw object, then [mne.make\_fixed\_length\_epochs](https://mne.tools/dev/generated/mne.make_fixed_length_epochs.html) could be what you are looking for.