[Eeglablist] Exporting events to text file - latency units

[Andrew Corcoran]

Dear Leo

Latency information refers to sample points; simply divide by the sampling
rate (EEG.srate) to recover time in milliseconds. The difference between
the two latencies you provide is ~2500 sample points, so I assume your
sampling rate is 250 Hz (250 samples/s * 10 s). It doesn't really make
sense to have non-integer sample points, but I think this can occur if you
downsample the data (event markers will be associated with a particular
sample point in the original event file, but may fall between points that
remain in the downsampled data).

Best
Andrew

On Sat, 10 Sept 2022 at 01:12, Leo Craemer via eeglablist <
eeglablist at sccn.ucsd.edu> wrote:

> Hello,
>
> I am currently partaking in an EEG project as part of my master’s
> dissertation and I am encountering a “problem" with EEGLAB. I hope this is
> the right place for this inquiry.
>
> I am exporting to text my events and I am not sure what unit I am seeing
> in the latency column. I was told to expect it to be milliseconds but that
> does not seem to be the case which makes adding events into this text file
> and then re-importing them back into EEGLAB problematic. I have a trigger
> at 126.16 seconds that shows up in event text file as latency =
> 65291.500000. Now for epoching I want another event 10 seconds before that
> which is completely fine to do with the EEGLAB GUI but when I inspect the
> text file I make from that it shows the new event at 62791.000000.
>
> What units is EEGLAB thinking in here and is there a way to simply export
> them as milliseconds/seconds?
>
> Info that might be useful:
>
>
>   *   I am on Mac 10.15.7
>   *   Matlab R2022_a
>   *   EEGLAB v2022.0
>
> Additional information that is necessary I will happily supply and
> apologies if there is already a thread discussing this issue.
>
> Kindest regards,
>
> Leo Craemer
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