


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. 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.
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. Defaults to 0. 0014 % e.g. For N = 500, if PAD = 0, we pad the FFT 0015 % to 512 points; if PAD = 2, we pad the FFT 0016 % to 2048 points, etc. 0017 % Fs (sampling frequency) - optional. Default 1. 0018 % fpass (frequency band to be used in the calculation in the form 0019 % [fmin fmax])- optional. 0020 % Default all frequencies between 0 and Fs/2 0021 % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars 0022 % [0 p] or 0 - no error bars) - optional. Default 0. 0023 % trialave (average over channels/trials when 1, don't average when 0) - optional. Default 0 0024 % fscorr (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional 0025 % (available only for spikes). Defaults 0. 0026 % t (time grid over which the tapers are to be calculated: 0027 % this argument is useful when calling the spectrum 0028 % calculation routine from a moving window spectrogram 0029 % calculation routine). If left empty, the spike times 0030 % are used to define the grid. 0031 % Output: 0032 % S (spectrum with dimensions frequency x channels/trials if trialave=0; dimension frequency if trialave=1) 0033 % f (frequencies) 0034 % R (rate) 0035 % Serr (error bars) - only if err(1)>=1 0036 if nargin < 1; error('Need data'); end; 0037 if nargin < 2; params=[]; end; 0038 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); 0039 if nargout > 3 && err(1)==0; error('cannot compute error bars with err(1)=0; change params and run again'); end; 0040 if nargin < 3 || isempty(fscorr); fscorr=0;end; 0041 if nargin < 4 || isempty(t); 0042 [mintime,maxtime]=minmaxsptimes(data); 0043 dt=1/Fs; % sampling time 0044 t=mintime-dt:dt:maxtime+dt; % time grid for prolates 0045 end; 0046 N=length(t); % number of points in grid for dpss 0047 nfft=2^(nextpow2(N)+pad); % number of points in fft of prolates 0048 [f,findx]=getfgrid(Fs,nfft,fpass); % get frequency grid for evaluation 0049 tapers=dpsschk(tapers,N,Fs); % check tapers 0050 [J,Msp,Nsp]=mtfftpt(data,tapers,nfft,Fs,t,f,findx); % mt fft for point process times 0051 S=squeeze(mean(conj(J).*J,2)); 0052 if trialave; S=squeeze(mean(S,2));Msp=mean(Msp);end; 0053 R=Msp*Fs; 0054 if nargout==4; 0055 if fscorr==1; 0056 Serr=specerr(S,J,err,trialave,Nsp); 0057 else 0058 Serr=specerr(S,J,err,trialave); 0059 end; 0060 end;