% LAPPLOT - Compute the discrete laplacian of EEG scalp distribution(s)
%
% Usage:
% >> laplace = lapplot(map,eloc_file,draw)
%
% Inputs:
% map - Activity levels, size (nelectrodes,nmaps)
% eloc_file - Electrode location filename (.loc file)
% For format, see >> topoplot example
% draw - If defined, draw the map(s) {default: no}
%
% Output:
% laplace - Laplacian map, size (nelectrodes,nmaps)
%
% Note: uses DEL2
%
% Author: Scott Makeig, SCCN/INC/UCSD, La Jolla, 1998
%
% See also: TOPOPLOT, GRADPLOT
% Copyright (C) Scott Makeig, SCCN/INC/UCSD, La Jolla, 1998
%
% This file is part of EEGLAB, see http://www.eeglab.org
% for the documentation and details.
%
% Redistribution and use in source and binary forms, with or without
% modification, are permitted provided that the following conditions are met:
%
% 1. Redistributions of source code must retain the above copyright notice,
% this list of conditions and the following disclaimer.
%
% 2. Redistributions in binary form must reproduce the above copyright notice,
% this list of conditions and the following disclaimer in the documentation
% and/or other materials provided with the distribution.
%
% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
% THE POSSIBILITY OF SUCH DAMAGE.
% 01-25-02 reformated help & license, added links -ad
function [laplac] = lapplot(map,filename,draw)
if nargin < 2
help lapplot;
return;
end
MAXCHANS = size(map,1);
GRID_SCALE = 2*MAXCHANS+5;
MAX_RADIUS = 0.5;
% ---------------------
% Read the channel file
% ---------------------
if ischar( filename )
fid = fopen(filename);
locations = fscanf(fid,'%d %f %f %s',[7 MAXCHANS]);
fclose(fid);
locations = locations';
Th = pi/180*locations(:,2); % convert degrees to rads
Rd = locations(:,3);
ii = find(Rd <= MAX_RADIUS); % interpolate on-scalp channels only
Th = Th(ii);
Rd = Rd(ii);
[x,y] = pol2cart(Th,Rd);
else
x = real(filename);
y = imag(filename);
end;
% ---------------------------------------------------
% Locate nearest position of an electrode in the grid
% ---------------------------------------------------
xi = linspace(-0.5,0.5,GRID_SCALE); % x-axis description (row vector)
yi = linspace(-0.5,0.5,GRID_SCALE); % y-axis description (row vector)
for i=1:MAXCHANS
[useless_var horizidx(i)] = min(abs(y(i) - xi)); % find pointers to electrode
[useless_var vertidx(i)] = min(abs(x(i) - yi)); % positions in Zi
end
% -----------------
% Compute laplacian
% -----------------
for i=1:size(map,2)
[Xi,Yi,Zi] = griddata(y,x,map(:,i),yi',xi, 'v4'); % interpolate data
laplac2D = del2(Zi);
positions = horizidx + (vertidx-1)*GRID_SCALE;
laplac(:,i) = laplac2D(positions(:));
% ------------------
% Draw laplacian map
% ------------------
if exist('draw');
mask = (sqrt(Xi.^2+Yi.^2) <= MAX_RADIUS);
laplac2D(find(mask==0)) = NaN;
subplot(ceil(sqrt(size(map,2))), ceil(sqrt(size(map,2))), i);
contour(laplac2D);
title( int2str(i) );
% %%% Draw Head %%%%
ax = axis;
width = ax(2)-ax(1);
axis([ax(1)-width/3 ax(2)+width/3 ax(3)-width/3 ax(4)+width/3])
steps = 0:2*pi/100:2*pi;
basex = .18*MAX_RADIUS;
tip = MAX_RADIUS*1.15;
base = MAX_RADIUS-.004;
EarX = [.497 .510 .518 .5299 .5419 .54 .547 .532 .510 .489];
EarY = [.0555 .0775 .0783 .0746 .0555 -.0055 -.0932 -.1313 -.1384 -.1199];
HCOLOR = 'k';
HLINEWIDTH = 1.8;
% Plot Head, Ears, Nose
hold on
plot(1+width/2+cos(steps).*MAX_RADIUS*width,...
1+width/2+sin(steps).*MAX_RADIUS*width,...
'color',HCOLOR,'Linestyle','-','LineWidth',HLINEWIDTH); % head
plot(1+width/2+[.18*MAX_RADIUS*width;0;-.18*MAX_RADIUS*width],...
1+width/2+[base;tip;base]*width,...
'Color',HCOLOR,'LineWidth',HLINEWIDTH); % nose
plot(1+width/2+EarX*width,...
1+width/2+EarY*width,...
'color',HCOLOR,'LineWidth',HLINEWIDTH) % l ear
plot(1+width/2-EarX*width,...
1+width/2+EarY*width,...
'color',HCOLOR,'LineWidth',HLINEWIDTH) % r ear
hold off
axis off
end
end;
return;
Datasets
Models
