You can create such a timing file manually, or use the 'marker'-analysistype to generate timing files automatically (see
marker ). Moreover, you
can do this quickly for a list of files using the batch
mode of anslab.general
timing
notes:
anslab has a very simple way to allow processing of selected
intervals of measured data: when a data file is read, anslab looks
for an m-file with the same name as the data file, in the folder
where the data file is stored. If this m-file exists, it is read
and timing is based on the T-variable defined in the m-file.
For instance, if for a data file
F:\tex\raw\tex00101.acq
an m-file
F:\tex\raw\tex00101.m
exists and it contains the following text:
T
= [...
2
0
1800 1800;...
1 1800
1903.519 103.519;...
3
NaN
NaN NaN;...
8 2130
2475.2 345.2 ];
anslab will recognize 4 valid segment definitions. The first
segment belongs to condition '2' and begins at 0 seconds after
file begin and ends at 1800 seconds after file begin, thus has a
length of 1800 seconds. The second interval (of condition '1')
starts at 1800 and ends at 1903.519 seconds after file begin,
spanning 103.519 seconds. The third line is a segment that cannot
be loaded, as begin and end time and duration are not valid timing
values, but will be filled with missing data when use for
statistical exports, icg, spectral or crossspectral analysis. The
fourth line again is a valid segment of condition 8.
You can create such a timing file manually, or use the
'marker'-analysistype to generate timing files automatically (see
marker ). Moreover, you
can do this quickly for a list of files using the batch
mode of anslab.
timing
fields:
As of version 2.6, anslab supports multiple timing 'fields' in a
single file. For instance, the above file could also look like
this:
T = [...
2
0
1800 1800;...
1 1800
1903.519 103.519;...
3
NaN
NaN NaN;...
8 2130
2475.2 345.2 ];
T.spectral = [...
2
0
600 600;...
1
600 1200
600;...
3 1200 1800
600;...
8 1800
2400 600 ];
thus containing an additional timing field 'spectral'. Having
multiple timing fields in a single file saves you the hassle of
managing and copying back and forth different versions of timing
files that you need for different type of tasks, such as value
export, spectral analysis, icg analysis, reflexive startle
analysis or trial extraction.
modifying
timing files:
Because timing files are so important for so many tasks in
anslab, there are two powerful tools to modify and adjust these
timing files to your specific needs: timing file modification
and timing file recoding. These are rule based replacement
tools for changing the condition values and the time values of
segments in a timing field. You can also collapse multiple
segments to a single segments or split a single segment into
several parts. Both of these tools are described at the 
tools-menu
description.
analyzing
event-related
designs:
To analyze
event-related designs with anslab, you should first of all process
all your data files as if you were interested in overall mean
values, that is to say, edit artifacts and extract event traces
over the entire file. If you have only a small amount of relevant
data segments and have marked segments of interest with a
dedicated marker channel, you can reduce the work by loading this
marker channel as 'optional channel' and editing only segments
that you jump to by using the 'find peak'-function from the
navigation section.
Once you have processed all the files of interest, you must create
timing files for every data file as described above (see marker for a detailed
description). This can be automatized using the batchmode of
anslab, activating the 'marker'-option in the dynamic
'batch'-module of anslab menu window. Later in the process anslab
will take every segment listed in the timing files and extract a
given number of seconds before and after the start of the segment. The
ending time is ignored in this case, to avoid signal length
differences due to timing rounding errors in the extracted trials.
Thus, you can select a subset of segments to include in the
extraction, by changing the timing file. Moreover, the first
column of the T-variable can be used to determine the naming of
the averaged segments later on.
You can automatically modifiy a set of timing files using the timing
file modification tool and the timing file recoding
tool described here.
Once you have prepared all this, use the 'extract trials'-item
from the event-menu, to extract data segments, corresponding the
trials in your experiment.