scalp: plot ERP waveforms in a scalp array
In erpR: Event-Related Potentials (ERP) Analysis, Graphics and Utility Functions

Description Usage Arguments Details Value Warning Warning Note Author(s) See Also Examples

This function plots the waveforms of several electrodes in an rectangular array reflecting their positions on the scalp

scalp(erpdfs, smo = NULL, layout = 1, 
ylims = "auto", yrev = TRUE, startmsec = NULL, endmsec = NULL, 
lwd = 1, lty = 1, color.list = c("blue", "red", "darkgreen"), 
legend = F, legend.lab = "default", t.axis = NULL, 
scalp.array=NULL)

`erpdfs`	a list indicating the ERP data frame to be plotted. All electrodes specified in the parameter `layout` will be plotted. The other electrodes will be ignored.
`smo`	the smoothing parameter to apply (see `smooth.spline`). Default is `NULL` and no smoothing is applied.
`layout`	A number indicating the layout of electrodes to be plotted. Currently only few default layouts are supported (a number from 1 to 5). Alternatively, a character vector specifying the layout may be supplied (see `Details`).
`ylims`	a number indicating the upper and lower limits of the y-axis. If "auto", the function calculates the y limits automatically.
`yrev`	logical. If `TRUE`, the y-axis is plotted with the negative values upward.
`startmsec`	the start time (in ms) of the ERP vector
`endmsec`	the end time (in ms) of the ERP vector
`lwd`	a vector specifying the line width to be associated with each ERP data frame specified in `categ`
`lty`	a vector specifying the line types to be associated with each ERP data frame specified in `categ`
`color.list`	a vector specifying the colors to be associated with each ERP data frame specified in `categ`
`legend`	logical. If `TRUE` a legend with object names is drawn in the top-right corner of the array.
`legend.lab`	the legend labels. If "default", the names are retrieved from `categ`.
`t.axis`	the position of the ticks on an additional axis indicating the time. This axis is plotted in the bottom-left corner of the plot array.
`scalp.array`	This argument is vector of two values indicating the number of panels of the plot, as number of rows and number of columns respectively. If a default layout is specified, the number of panels is automatically computed. See also `Details`.

The layout parameter can be a number (from 1 to 5), that specifies some default electrode arrangements (currently only a few default arrangements are supported). Otherwise, the argument may be a character vector indicating the names of the electrodes to be plotted. The plot is divided in a number of panels as specified in scalp.array. The names specified will be plotted from top to bottom and from left to right. If "blank" is specified an empty panel will be plotted. If "xaxis" is specified a x axis indicating time will be plotted. If "yaxis" is specified a y axis indicating voltage will be plotted.

The function plots a map of ERP waveforms in an array resembling the topographic locations of the electrodes on the scalp.

In categ argument, a list must be specified even if only one object is plotted.

in the categ argument, a list must be specified even if the plot is on only one object

Currently this function supports a very limited number of layouts. Further versions will allow to specify customized layouts.

Giorgio Arcara

scalp.t, scalp.infl, erp

data(erplistExample)

word=grandaverage("Exp1_word_subj", 1:20, erplist=erplistExample)

nonword=grandaverage("Exp1_nonword_subj", 1:20, erplist=erplistExample)

scalp(word, layout=1, ylim=10)

scalp(list(word, nonword), layout=1, ylim=10, legend=TRUE)