


Multi-taper spectrum - point process times
Usage:
[S,f,R,Serr]=mtspectrumpt(data,params,fscorr,t)
Input:
data (structure array of spike times with dimension channels/trials; also accepts 1d array of spike times) -- required
params: structure with fields tapers, pad, Fs, fpass, err, trialave
- 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.
trialave (average over channels/trials when 1, don't average when 0) - optional. Default 0
fscorr (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional
(available only for spikes). Defaults 0.
t (time grid over which the tapers are to be calculated:
this argument is useful when calling the spectrum
calculation routine from a moving window spectrogram
calculation routine). If left empty, the spike times
are used to define the grid.
Output:
S (spectrum with dimensions frequency x channels/trials if trialave=0; dimension frequency if trialave=1)
f (frequencies)
R (rate)
Serr (error bars) - only if err(1)>=1

0001 function [S,f,R,Serr]=mtspectrumpt(data,params,fscorr,t) 0002 % Multi-taper spectrum - point process times 0003 % 0004 % Usage: 0005 % 0006 % [S,f,R,Serr]=mtspectrumpt(data,params,fscorr,t) 0007 % Input: 0008 % data (structure array of spike times with dimension channels/trials; also accepts 1d array of spike times) -- required 0009 % params: structure with fields tapers, pad, Fs, fpass, err, trialave 0010 % - optional 0011 % tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 0012 % specified, use [NW K]=[3 5] 0013 % pad (padding factor for the FFT) - optional (can take values -1,0,1,2...). 0014 % -1 corresponds to no padding, 0 corresponds to padding 0015 % to the next highest power of 2 etc. 0016 % e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT 0017 % to 512 points, if pad=1, we pad to 1024 points etc. 0018 % Defaults to 0. 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 % trialave (average over channels/trials when 1, don't average when 0) - optional. Default 0 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 % t (time grid over which the tapers are to be calculated: 0029 % this argument is useful when calling the spectrum 0030 % calculation routine from a moving window spectrogram 0031 % calculation routine). If left empty, the spike times 0032 % are used to define the grid. 0033 % Output: 0034 % S (spectrum with dimensions frequency x channels/trials if trialave=0; dimension frequency if trialave=1) 0035 % f (frequencies) 0036 % R (rate) 0037 % Serr (error bars) - only if err(1)>=1 0038 if nargin < 1; error('Need data'); end; 0039 if nargin < 2; params=[]; end; 0040 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0041 clear params 0042 data=change_row_to_column(data); 0043 if nargout > 3 && err(1)==0; error('cannot compute error bars with err(1)=0; change params and run again'); end; 0044 if nargin < 3 || isempty(fscorr); fscorr=0;end; 0045 if nargin < 4 || isempty(t); 0046 [mintime,maxtime]=minmaxsptimes(data); 0047 dt=1/Fs; % sampling time 0048 t=mintime-dt:dt:maxtime+dt; % time grid for prolates 0049 end; 0050 N=length(t); % number of points in grid for dpss 0051 nfft=max(2^(nextpow2(N)+pad),N); % number of points in fft of prolates 0052 [f,findx]=getfgrid(Fs,nfft,fpass); % get frequency grid for evaluation 0053 tapers=dpsschk(tapers,N,Fs); % check tapers 0054 [J,Msp,Nsp]=mtfftpt(data,tapers,nfft,t,f,findx); % mt fft for point process times 0055 S=squeeze(mean(conj(J).*J,2)); 0056 if trialave; S=squeeze(mean(S,2));Msp=mean(Msp);end; 0057 R=Msp*Fs; 0058 if nargout==4; 0059 if fscorr==1; 0060 Serr=specerr(S,J,err,trialave,Nsp); 0061 else 0062 Serr=specerr(S,J,err,trialave); 0063 end; 0064 end;