


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 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 (can take values -1,0,1,2...).
-1 corresponds to no padding, 0 corresponds to padding
to the next highest power of 2 etc.
e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
to 512 points, if pad=1, we pad to 1024 points etc.
Defaults to 0.
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 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 (can take values -1,0,1,2...). 0016 % -1 corresponds to no padding, 0 corresponds to padding 0017 % to the next highest power of 2 etc. 0018 % e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT 0019 % to 512 points, if pad=1, we pad to 1024 points etc. 0020 % Defaults to 0. 0021 % Fs (sampling frequency) - optional. Default 1. 0022 % fpass (frequency band to be used in the calculation in the form 0023 % [fmin fmax])- optional. 0024 % Default all frequencies between 0 and Fs/2 0025 % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars 0026 % [0 p] or 0 - no error bars) - optional. Default 0. 0027 % segave - (0 for don't average over segments, 1 for average) - optional - default 1 0028 % fscorr (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional 0029 % (available only for spikes). Defaults 0. 0030 % Output: 0031 % S (spectrum in form frequency x segments if segave=0; function of frequency if segave=1) 0032 % f (frequencies) 0033 % R (spike rate) 0034 % varS (variance of the spectrum as a function of frequency) 0035 % zerosp (0 for segments in which spikes were found, 1 for segments 0036 % C (covariance matrix of the log spectrum - frequency x 0037 % frequency matrix) 0038 % Serr (error bars) - only if err(1)>=1 0039 0040 if nargin < 2; error('Need data and segment information'); end; 0041 if nargin < 3; params=[]; end; 0042 if nargin < 4 || isempty(segave); segave=1; end; 0043 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0044 clear params trialave 0045 if nargin < 5 || isempty(fscorr); fscorr=0;end; 0046 0047 if nargout > 4 && err(1)==0; error('cannot compute error bars with err(1)=0; change params and run again'); end; 0048 0049 dtmp=change_row_to_column(data); 0050 T=max(dtmp); % total length of data 0051 minT=min(dtmp); 0052 E=minT:win:T-win; % fictitious event triggers 0053 win=[0 win]; % use window length to define left and right limits of windows around triggers 0054 dtmp=createdatamatpt(dtmp,E,win); % create segmented data set 0055 [mintime,maxtime]=minmaxsptimes(dtmp); 0056 dt=1/Fs; % sampling time 0057 t=mintime-dt:dt:maxtime+dt; % time grid for prolates 0058 N=length(t); % number of points in grid for dpss 0059 nfft=max(2^(nextpow2(N)+pad),N); % number of points in fft of prolates 0060 [f,findx]=getfgrid(Fs,nfft,fpass); % get frequency grid for evaluation 0061 tapers=dpsschk(tapers,N,Fs); % check tapers 0062 [J,Msp,Nsp]=mtfftpt(dtmp,tapers,nfft,t,f,findx);% mt fft for point process times 0063 R=Msp*Fs; 0064 S=squeeze(mean(conj(J).*J,2)); % spectra of non-overlapping segments (averaged over tapers) 0065 if segave==1; SS=squeeze(mean(S,2));R=mean(R);else;SS=S;end;% mean of the spectrum averaged across segments 0066 if nargout > 3 0067 lS=log(SS); % log spectrum for nonoverlapping segments 0068 % varS=var(lS,1,2); % variance of log spectrum 0069 varS=var(lS',1)';% variance of the log spectrum R13 0070 if nargout > 4 0071 zerosp=zeros(1,size(data,2)); 0072 zerosp(Nsp==0)=1; 0073 if nargout > 5 0074 C=cov(lS'); % covariance matrix of the log spectrum 0075 if nargout==7; 0076 if fscorr==1; 0077 Serr=specerr(SS,J,err,segave,Nsp); 0078 else 0079 Serr=specerr(SS,J,err,segave); 0080 end; 0081 end; 0082 end; 0083 end; 0084 end; 0085 S=SS;