avraverage - ERP Grand Averaging

Contents

Synopsis


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EEP 3.1  Max-Planck-Institute of Cognitive Neuroscience 1996-99
avraverage 3.18   (OSF1 V4.0 alpha)           Wed Sep 15 13:30:26 1999
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  avraverage <cfg> <output dir> [<output filename base>]


Configuration File

; Example configuration file for avraverage


; the input .avr filenames are built from the template
; by expandig "&t" with the condition code and "&s" with 
; the subject code below
[filename template]
./&s/a1rf/&s&t.avr

; subject codes to build the .avr filenames ("&s")
[subjects]
pi01
pi12

; condition codes to build the .avr filenames ("&t")
; a grand average is computed for each condition here
; from all subject listed above
[conditions]
1
2

[weighted]
no    ; each average is weighted with 1.0
;sn   ; to weight each input average with sqrt(Ntrials)
;cum  ; accumulate the single trials from the input averages

; list of channels for output averages
; you can comment out this section to request the largest common 
; subset of channels available

;[channels]
;F9, F7, F5, F3, FZ, F4, F6, F8, F10
;EOGV, EOGH

; output average time range
; you can comment out this section to request the largest common 
; time range available
; (values have to be separated by exact two dots, no whitespaces)

;[time range]
;-200..1200        ; ms


; For latency jitter compensation: An avrretrieve-like ASCII table 
; is read (here: foo.tab);  the [time range] window above is 
; interpreted relative to the latency in the given column (here: tgmin)
; then, not relative to 0 in the .avr file.
;
; The correct line is found by matching subj, cond, chan of each input
; avr vector with the "subj", "cond", "chan" columns of the ASCII table,
; whichever are present.

;[time base]
;foo.tab  tgmin


Description

Performing a study using the EEP software results in one or more four-dimensional ERP datasets (subject * condition * channel * time). Each dataset consists of several two-dimensional matrix files (.avr files - containing a channel * time matrix). These files are stored in a directory tree which naming conventions encode the (subject * condition) dimensions of the study.

avraverage gives you access tho the full dataset, allows selection in all 4 dimensions and can derive grand averages from the selected input averages.

The input filelist generation is designed for computing one grand average per listed condition, each one from all listed subjects. This complements the filename rules introduced by the cntaverage module. See the more flexible avrprocess module if these rules do not match your needs.

Former versions of avraverage had options for generating "SAS output". While this functionality is still present, it is obsolete now and replaced by avrretrieve.

File Naming

The output filenames are generated from the [conditions] codes and the command line arguments as follows:

avraverage grand_av.cfg test run
would produce the result files:

./test/run.n             numbers of trials in the input files
./test/runc1.avr         one grand average for 
./test/runc2.avr         each listed condition
...

EEP 3.1 - MPI/ANT(eeprobe@ant-software.nl), 15.09.1999
Copyright © 1996-99 Max-Planck-Institute of Cognitive Neuroscience. All rights reserved.