FilterLFP

FilterLFP - Filter the local field potentials, e.g. in the theta band.

 Filter the local field potentials using a cheby2 filter.

  USAGE

    filtered = FilterLFP(lfp,<options>)

    lfp            local field potentials <a href="matlab:help samples">samples</a>
    <options>      optional list of property-value pairs (see table below)

    =========================================================================
     Properties    Values
    -------------------------------------------------------------------------
     'passband'    frequency range (default = [4 10], 'theta')
     'order'       filter order (default = 4, but see NOTE below)
     'ripple'      filter ripple (default = 20)
     'nyquist'     nyquist frequency (default = 625)
     'filter'      choose filter type between 'cheby2' (default) and 'fir1'
    =========================================================================

  NOTE

    The passband can be supplied either explicitly, e.g. [30 80], or by name,
    by choosing among the following predefined frequency bands:

        delta      [0 6] (order = 8)
        theta      [4 10]
        spindles   [9 17]
        gamma      [30 80]
        ripples    [100 250]

0001 function filtered = FilterLFP(lfp,varargin)
0002 
0003 %FilterLFP - Filter the local field potentials, e.g. in the theta band.
0004 %
0005 % Filter the local field potentials using a cheby2 filter.
0006 %
0007 %  USAGE
0008 %
0009 %    filtered = FilterLFP(lfp,<options>)
0010 %
0011 %    lfp            local field potentials <a href="matlab:help samples">samples</a>
0012 %    <options>      optional list of property-value pairs (see table below)
0013 %
0014 %    =========================================================================
0015 %     Properties    Values
0016 %    -------------------------------------------------------------------------
0017 %     'passband'    frequency range (default = [4 10], 'theta')
0018 %     'order'       filter order (default = 4, but see NOTE below)
0019 %     'ripple'      filter ripple (default = 20)
0020 %     'nyquist'     nyquist frequency (default = 625)
0021 %     'filter'      choose filter type between 'cheby2' (default) and 'fir1'
0022 %    =========================================================================
0023 %
0024 %  NOTE
0025 %
0026 %    The passband can be supplied either explicitly, e.g. [30 80], or by name,
0027 %    by choosing among the following predefined frequency bands:
0028 %
0029 %        delta      [0 6] (order = 8)
0030 %        theta      [4 10]
0031 %        spindles   [9 17]
0032 %        gamma      [30 80]
0033 %        ripples    [100 250]
0034 
0035 % Copyright (C) 2004-2015 by Michaël Zugaro
0036 %
0037 % This program is free software; you can redistribute it and/or modify
0038 % it under the terms of the GNU General Public License as published by
0039 % the Free Software Foundation; either version 3 of the License, or
0040 % (at your option) any later version.
0041 
0042 % Default values
0043 passband = [4 10];
0044 order = 4;
0045 
0046 % Check number of parameters
0047 if nargin < 1 | mod(length(varargin),2) ~= 0,
0048     error('Incorrect number of parameters (type ''help <a href="matlab:help FilterLFP">FilterLFP</a>'' for details).');
0049 end
0050 
0051 % Check parameter sizes
0052 if ~isdmatrix(lfp),
0053     error('Parameter ''lfp'' is not a matrix (type ''help <a href="matlab:help FilterLFP">FilterLFP</a>'' for details).');
0054 end
0055 
0056 % Parse parameter list
0057 i = 1;
0058 while i <= length(varargin),
0059     if ~ischar(varargin{i}),
0060         error(['Parameter ' num2str(i) ' is not a property (type ''help <a href="matlab:help FilterLFP">FilterLFP</a>'' for details).']);
0061     end
0062     switch(lower(varargin{i})),
0063         case 'passband',
0064             passband = varargin{i+1};
0065             if isastring(passband),
0066                 switch(lower(passband)),
0067                     case 'delta',
0068                         passband = [0 6];
0069                         order = 8;
0070                     case 'theta',
0071                         passband = [4 10];
0072                     case 'spindles',
0073                         passband = [9 17];
0074                     case 'gamma',
0075                         passband = [30 80];
0076                     case 'ripples',
0077                         passband = [100 250];
0078                     otherwise,
0079                         error(['Unknown frequency band ''' passband ''' (type ''help <a href="matlab:help FilterLFP">FilterLFP</a>'' for details).']);
0080                 end
0081             elseif ~isdvector(passband,'#2','>=0'),
0082                 error('Incorrect value for ''passband'' (type ''help <a href="matlab:help FilterLFP">FilterLFP</a>'' for details).');
0083             end
0084             varargin = {varargin{[1:(i-1) (i+2):length(varargin)]}};
0085         otherwise,
0086             i = i+2;
0087     end
0088 end
0089 filtered = Filter(lfp,'passband',passband,'order',order,varargin{:});