Analyzing EEG data without events/epochs?

Dear forum,

I have a question regarding my EEG analysis. I conducted experiments where participants watched videos in 3D and 2D and I want to compare the EEG data in those conditions. Therefore, I don’t have any events in my data (the participants were just watching the videos). Do I need to use epochs? Can I treat the whole EEG segment as one epoch?

I want to do some basic spectral analysis to see whether there is more acitivty in certain frequency bands during the 2D and the 3D condition.

Is that possible?

More details:
First I made a 2 min baseline recording. Then, the participants were placed infront of a screen (2D) or used VR glasses (3D). Afterwards, I read a problem statement to them and they had to come up with creative solutions towards the problem. The EEG recording took about 5 min. in total, and the participants had some 20 seconds windows to unload their ideas. My approach so far was to remove those 20 second windows immediately so that I’m left with only the “thinking” intervals and I wanted to treat it as it was one epoch. However, I encountered several problems with this approach and it seems like I need to use events and epochs. But the problem is that the participants are not reacting to an external stimuli during my experiment as they are just watching the video and thinking about creative ideas.

So how can I analyse the data?

mne.time_frequency.psd_welch and psd_multitaper can both operate on Raw objects.