function EEGfiltered = eeg_filter(EEGinput,sample_freq,lcf,hcf,order);

% eeg_filter - apply a butterworth polynomial filter
%
%   Usage : EEGfiltered = eeg_filter(EEGinput,sample_freq,lcf,hcf,order)
%
%   - input arguments
%       EEGinput    : eeg data - M samples x N channels x P epochs
%       sample_freq : sampling frequency
%       lcf         : low cutoff frequency (highpass, default 0.01)
%       hcf         : high cutoff frequency (lowpass, default 40)
%       order       : butterworth polynomial order (default 2)
%
%   - output argument
%       EEGfiltered : filtered EEGinput;