erp.peak {erpR} | R Documentation |
This function calculates the peak amplitude on several ERP data frame. It returns results in wide format (each electrode in a separate column) or in long format which is more suitable for standard statistical analysis in R (e.g. ANOVA). erp.peak
applies the function mean
to several ERP data frames with timepoints in rows and electrodes in columns. ERP data frames are expected to be named as a combination of strings specified in base
and numbers
.
erp.peak(base, numbers, win.ini, win.end, erplist = NULL, startmsec=NULL, endmsec=NULL, others=NULL, format="long", name.dep="Dep", name.newvar="electrode", peak.fun = "max", numbers.name="Subject", ...)
base |
a string indicating the beginning of the name of |
numbers |
the numbers of the subjects to be averaged by the function. |
win.ini |
the initial edge (in ms) of the window on which the peak amplitude has to be computed. |
win.end |
the final edge (in ms) of the window on which the peak amplitude has to be computed. |
erplist |
a list containing the ERP data frames specified in |
startmsec |
the start time (in ms) of the ERP data frames. It can be a negative value, indicating the baseline time frame. |
endmsec |
the end time (in ms) of the ERP data frames. |
others |
the names of other variables to be included in the returned data frame. Ignored if the format is "wide". |
format |
the output format. It may be "wide" or "long". |
name.dep |
the name of the dependent variable in the returned data frame. Ignored if the format is "wide". |
peak.fun |
the function to calculate the peak. Available functions are |
name.newvar |
If the format is "long", the name of the new variable codifying the electrodes. Default is "electrode". |
... |
arguments passed to the function specified in |
numbers.name |
The name of the new column (in the output |
The function takes an ERP data frame with electrodes in separate columns as input. If the format is long, this function returns a data frame in long format ready for standard statistical analysis in R. The returned data frame has one column for dependent variable and a new factor "electrode". The erpR
functions localmax
and localmin
are are written following Luck (2005).
A ERP data frame with peak amplitude in long or wide format. Two more columns are added: the column Subject
indicates the subject number
; the column Subject_name
reports the string retrieved from the comment of the data frame (see Details on import.erp
).
This function calls rearrange
.
Giorgio Arcara
Luck, S., J. (2005). An Introduction to the Event-Related Potential Technique. Cambridge, Mass.: The MIT Press.
erp.mean
, erp.latency
, rearrange
, max
, min
, localmax
, localmin
data(erplistExample) dat=erp.peak(base="Exp1_word_subj", numbers=1:20, win.ini=130, win.end=190, erplist=erplistExample, others=c(condition="word", interval="130-190"), name.dep="Ampl", format="long", peak.fun=max)