The Neurophysiological Biomarker Toolbox (NBT)

## The NBT signal viewer

NBT contains the function nbt_plot to plot your signals, with some extra features besides the standard Matlab options. Before the plot appears, a popup window will let you specify several settings for the plot: the channels to be plotted, the time interval, the frequency interval, the units at the x-axis, the colors of the signals, and the vertical distance between the signals. Once the plot is generated these settings can be edited by clicking the “edit plot parameters” button at the upper right of the figure. In case of EEG data, the channels to be plotted can be selected interactively (see figure below). The buttons at the figure allow to scroll in time and through channels. In the plot, right click on a channel to display the channel number.

Usage: first load a NBT Signal (see The NBT GUI and loading a NBT Signal. Then, in the NBT GUI, select Visualization|Plot Signals. Here is a screenshot of how the plot can look :

And a movie showing the possibilities:

This function can also be called from the command window:

nbt_plot(Signal,SignalInfo,timescale,frequencyinterval,filterorder,add_legend,addcolors,distance,linepoint)

Inputs:
Signal = NBT Signal matrix
SignalInfo = NBT Info object
timescale = 'minutes' or 'seconds'. Sets the time scale and units for plotting (default = no conversion to time units, units are samples)
frequencyinterval = 1-by-2 vector, containing the frequencies of the butterworth bandpass-filter interval (default = no filtering)
filterorder = double, order of butterworth filter (default = 4)
add_legend = logical (0 or 1), 1 means add legend (default = 0)
add_colors = logical (0 or 1), 1 means plot each signal with a different color (default = 1)
distance = double, the distance in vertical direction between the signals in the plot (default = 6*median of standard deviations of signals)
linepoint = character, 'L' means plot line between samples, 'P' means plot line between samples and individual samples as points.

For example:

nbt_plot(Signal,SignalInfo,'samples',[1  45],4,0,'n',38.4302,'L')

Only the inputs Signal and SignalInfo are obligatory, the other parameters can be left out or be empty. The channels and time interval to be plotted can be set at the beginning of the function nbt_plot.