DEL2MAP Compute the discrete laplacian of an EEG distribution.

Usage: >> [ laplac ] = del2map( map, filename, draw );

Inputs:
map   
level of activity (size: nbChannel)
filename   
filename (.loc file) countaining the coordinates of the electrodes, or array countaining complex positions
draw   
integer, if not nul draw the gradient (default:0)

Output:
laplac   
laplacian map. If the input values are in microV and the the sensors placement are in mm, the output values are returned in microV/mm^2. In order to use current density units like milliamps/mm2, you would need to know skin conductance information, which as far as we know is not really known with enough accuracy to be worthwhile.

Author: Arnaud Delorme, CNL / Salk Institute, 2001
Thanks Ramesh Srinivasan and Tom Campbell for the discussion
on laplacian output units.

See the matlab file del2map.m (may require other functions)

Back to functions