


Multi-taper segmented spectrum for a univariate binned point process
Usage:
[S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpt(data,win,params,segave,fscorr)
Input:
Note units have to be consistent. See chronux.m for more information.
data (structure array of one channel of spike times; also accepts 1d column vector of spike times) -- required
win (duration of the segments) - required.
params: structure with fields tapers, pad, Fs, fpass, err
- optional
tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not
specified, use [NW K]=[3 5]
pad (padding factor for the FFT) - optional. Defaults to 0.
e.g. For N = 500, if PAD = 0, we pad the FFT
to 512 points; if PAD = 2, we pad the FFT
to 2048 points, etc.
Fs (sampling frequency) - optional. Default 1.
fpass (frequency band to be used in the calculation in the form
[fmin fmax])- optional.
Default all frequencies between 0 and Fs/2
err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
[0 p] or 0 - no error bars) - optional. Default 0.
segave - (0 for don't average over segments, 1 for average) - optional - default 1
fscorr (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional
(available only for spikes). Defaults 0.
Output:
S (spectrum in form frequency x segments if segave=0; function of frequency if segave=1)
f (frequencies)
R (spike rate)
varS (variance of the spectrum as a function of frequency)
zerosp (0 for segments in which spikes were found, 1 for segments
C (covariance matrix of the log spectrum - frequency x
frequency matrix)
Serr (error bars) - only if err(1)>=1

0001 function [S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpt(data,win,params,segave,fscorr) 0002 % Multi-taper segmented spectrum for a univariate binned point process 0003 % 0004 % Usage: 0005 % 0006 % [S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpt(data,win,params,segave,fscorr) 0007 % Input: 0008 % Note units have to be consistent. See chronux.m for more information. 0009 % data (structure array of one channel of spike times; also accepts 1d column vector of spike times) -- required 0010 % win (duration of the segments) - required. 0011 % params: structure with fields tapers, pad, Fs, fpass, err 0012 % - optional 0013 % tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 0014 % specified, use [NW K]=[3 5] 0015 % pad (padding factor for the FFT) - optional. Defaults to 0. 0016 % e.g. For N = 500, if PAD = 0, we pad the FFT 0017 % to 512 points; if PAD = 2, we pad the FFT 0018 % to 2048 points, etc. 0019 % Fs (sampling frequency) - optional. Default 1. 0020 % fpass (frequency band to be used in the calculation in the form 0021 % [fmin fmax])- optional. 0022 % Default all frequencies between 0 and Fs/2 0023 % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars 0024 % [0 p] or 0 - no error bars) - optional. Default 0. 0025 % segave - (0 for don't average over segments, 1 for average) - optional - default 1 0026 % fscorr (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional 0027 % (available only for spikes). Defaults 0. 0028 % Output: 0029 % S (spectrum in form frequency x segments if segave=0; function of frequency if segave=1) 0030 % f (frequencies) 0031 % R (spike rate) 0032 % varS (variance of the spectrum as a function of frequency) 0033 % zerosp (0 for segments in which spikes were found, 1 for segments 0034 % C (covariance matrix of the log spectrum - frequency x 0035 % frequency matrix) 0036 % Serr (error bars) - only if err(1)>=1 0037 0038 if nargin < 2; error('Need data and segment information'); end; 0039 if nargin < 3; params=[]; end; 0040 if nargin < 4 || isempty(segave); segave=1; end; 0041 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0042 if nargin < 5 || isempty(fscorr); fscorr=0;end; 0043 0044 if nargout > 4 && err(1)==0; error('cannot compute error bars with err(1)=0; change params and run again'); end; 0045 0046 if isstruct(data); 0047 fnames=fieldnames(data); 0048 eval(['dtmp=data.' fnames{1} ';']) 0049 else 0050 dtmp=data(:); 0051 end; 0052 T=max(dtmp); % total length of data - USED???? 0053 minT=min(dtmp); 0054 dt=1/Fs; % sampling interval 0055 E=minT:win:T-win; % fictitious event triggers 0056 win=[0 win]; % use window length to define left and right limits of windows around triggers 0057 dtmp=createdatamatpt(dtmp,E,win); % create segmented data set 0058 zerosp=zeros(1,size(data,1)); 0059 [mintime,maxtime]=minmaxsptimes(dtmp); 0060 dt=1/Fs; % sampling time 0061 t=mintime-dt:dt:maxtime+dt; % time grid for prolates 0062 N=length(t); % number of points in grid for dpss 0063 nfft=2^(nextpow2(N)+pad); % number of points in fft of prolates 0064 [f,findx]=getfgrid(Fs,nfft,fpass); % get frequency grid for evaluation 0065 tapers=dpsschk(tapers,N,Fs); % check tapers 0066 [J,Msp,Nsp]=mtfftpt(dtmp,tapers,nfft,Fs,t,f,findx);% mt fft for point process times 0067 zerosp(find(Nsp==0))=1; 0068 R=Msp*Fs; 0069 S=squeeze(mean(conj(J).*J,2)); % spectra of non-overlapping segments (averaged over tapers) 0070 lS=log(S); % log spectrum 0071 C=cov(lS')'; % covariance matrix of the log spectrum 0072 varS=diag(C); % variance of fthe log spectrum 0073 if segave==1; S=squeeze(mean(S,2)); R=squeeze(mean(R)); end; % mean of the spectrum averaged across segments and tapers 0074 if nargout==6; 0075 if fscorr==1; 0076 Serr=specerr(S,J,err,trialave,Nsp); 0077 else 0078 Serr=specerr(S,J,err,trialave); 0079 end; 0080 end;