Troubles in apply_baseline

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1

I used the sentence below to do baseline correction. However, the signal doesn’t change. Could anyone tell me why? Thanks.

tmin, tmax = -0.2, 1
epochs = mne.Epochs(raw, events, tmin=tmin, tmax=tmax)
epochs.plot(n_epochs=10, events=True)
epochs.average().apply_baseline((tmin,tmax))
epochs.plot(n_epochs=10, events=True)

Out[11]: <Evoked | ‘0.00 × 21 + 0.00 × 22 + 0.00 × 41 + 0.00 × 42 + 0.00 × 61 + 0.00 × 62 + 0.33 × 111 + 0.67 × 112 + 0.00 × 121 + 0.00 × 122’ (average, N=1), -0.2 – 1 s, baseline -0.2 – 1 s, 59 ch, ~604 kB>

2

This creates an Evoked object, applies baseline correction to it, and discards the results since you don’t assign the result of epochs.average() to a new variable.

Also, using the entire duration of the epochs as baseline doesn’t seem very logical to me… you may want to reconsider this.

Best wishes,
Richard

3

Thanks. But the problem is still unsolved.

I write:
bb = epochs.average()
cc = bb.apply_baseline()

and found no difference between bb and cc.

4

I tried

bb = epochs[1].average()
bb.plot()
cc = bb.apply_baseline((tmin, tmax))
cc.plot()

and I saw the difference finally. Thanks.