Practially is there any correlation between data collected from different areas

I have EEG data from two different regions, collected by the same device for the same purpose. I was trying to find a correlation between the region. I think there should be some correlation, but the heat map shows very little correlation. Is it a normal thing.? As i can see a high correlation in region A data set in top left and medium correlation in region B dataset in the bottom right side of the image. And now the correlation between both regions.

Practically does correlation exist between data collected from same region?
Practically does correlation exist between data collected from different region?

My aim is to train my machine learning model on one dataset and test on another region dataset. But i failed to do so. SO I was checking correlation. Though my model work when tested on same region dataset and flopped when tested on another region dataset.

Data are averaged across subjects before taking correlation.

Hi talha. That correlation matrix looks very strange. Neighboring electrodes should have very similar correlation patterns, but, for example, O1 and O2 look quite different from each other. And P7-O2 look more similar than P7-O1? Also doesn’t make any sense.

I have no idea what these are correlations of, or how you averaged across subjects before correlating, but you might want to go back to the raw within-subject data and looking at those correlation matrices. Perhaps the electrode labels are incorrectly aligned? Again, I don’t know what the problem is, but there’s no point is trying to run deeper analyses until you are confident that the data are OK.

Seems i mislabeled the electrode, but now i have corrected. But the trend , you have point is the same.
I have averaged all subject for one region in following image

In image below, data is averaged and the correlation is found

In the image below, correlation heatmap is created for each subject and then these correlation matrix are averaged