[Eeglablist] latencies in continuous and epoch data

[Petr Janata]

Hi,

I'm puzzled by how latencies should be specified for events in epoch 
data.

My continuous EEG datafiles are too large to load and parse into epochs 
using the EEGLAB routines, so I am writing my own script to chop up the 
continuous data into the epochs I want and then fill and store the 
resulting EEG structure.  However, importing latency info is proving 
problematic because I don't know how time is represented in epoch data.

Is the sample value that is stored in EEG.event(idx).latency supposed 
to equal:

(current_epoch_idx-1)*nsamps_per_epoch + samp_offset_of_event_in_epoch

The EEGLAB documentation, while very good and helpful, is not explicit 
about the way "continuous" time is represented in epoch data, so I just 
thought I'd ask.

Many thanks.

Petr


------------------
Petr Janata, Ph.D.
Research Assistant Professor
Department of Psychological and Brain Sciences, and
Center for Cognitive Neuroscience
Dartmouth College
Hanover, NH 03755

phone: 603 646 0062
fax: 603 646 1419
e-mail: petr.janata at dartmouth.edu
WWW: http://atonal.dartmouth.edu/~petr