coherencycpb.m 5.4 KB

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  1. function [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencycpb(data1,data2,params,fscorr)
  2. % Multi-taper coherency,cross-spectrum and individual spectra - continuous and binned point process data
  3. %
  4. % Usage:
  5. %
  6. % [C,phi,S12,S1,S2,f,zerosp,confC,phistd,Cerr]=coherencycpb(data1,data2,params,fscorr)
  7. % Inputs:
  8. % data1 (continuous data in form samples x trials) -- required
  9. % data2 (binned spike data in form samples x trials) -- required
  10. % params: structure with fields tapers, pad, Fs, fpass, err, trialave
  11. % - optional
  12. % tapers : precalculated tapers from dpss or in the one of the following
  13. % forms:
  14. % (1) A numeric vector [TW K] where TW is the
  15. % time-bandwidth product and K is the number of
  16. % tapers to be used (less than or equal to
  17. % 2TW-1).
  18. % (2) A numeric vector [W T p] where W is the
  19. % bandwidth, T is the duration of the data and p
  20. % is an integer such that 2TW-p tapers are used. In
  21. % this form there is no default i.e. to specify
  22. % the bandwidth, you have to specify T and p as
  23. % well. Note that the units of W and T have to be
  24. % consistent: if W is in Hz, T must be in seconds
  25. % and vice versa. Note that these units must also
  26. % be consistent with the units of params.Fs: W can
  27. % be in Hz if and only if params.Fs is in Hz.
  28. % The default is to use form 1 with TW=3 and K=5
  29. %
  30. % pad (padding factor for the FFT) - optional (can take values -1,0,1,2...).
  31. % -1 corresponds to no padding, 0 corresponds to padding
  32. % to the next highest power of 2 etc.
  33. % e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
  34. % to 512 points, if pad=1, we pad to 1024 points etc.
  35. % Defaults to 0.
  36. % Fs (sampling frequency) - optional. Default 1.
  37. % fpass (frequency band to be used in the calculation in the form
  38. % [fmin fmax])- optional.
  39. % Default all frequencies between 0 and Fs/2
  40. % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
  41. % [0 p] or 0 - no error bars) - optional. Default 0.
  42. % trialave (average over trials when 1, don't average when 0) - optional. Default 0
  43. % fscorr (finite size corrections, 0 (don't use finite size corrections) or 1
  44. % (use finite size corrections) - optional (available only for spikes). Defaults 0.
  45. % Outputs:
  46. % C (magnitude of coherency - frequencies x trials if trialave=0; dimension frequencies if trialave=1)
  47. % phi (phase of coherency - frequencies x trials if trialave=0; dimension frequencies if trialave=1)
  48. % S12 (cross spectrum - frequencies x trials if trialave=0; dimension frequencies if trialave=1)
  49. % S1 (spectrum 1 - frequencies x trials if trialave=0; dimension frequencies if trialave=1)
  50. % S2 (spectrum 2 - frequencies x trials if trialave=0; dimension frequencies if trialave=1)
  51. % f (frequencies)
  52. % zerosp (1 for trials where no spikes were found, 0 otherwise)
  53. % confC (confidence level for C at 1-p %) - only for err(1)>=1
  54. % phistd - theoretical/jackknife (depending on err(1)=1/err(1)=2) standard deviation for phi
  55. % Note that phi + 2 phistd and phi - 2 phistd will give 95% confidence
  56. % bands for phi - only for err(1)>=1
  57. % Cerr (Jackknife error bars for C - use only for Jackknife - err(1)=2)
  58. if nargin < 2; error('Need data1 and data2'); end
  59. if nargin < 3; params=[]; end;
  60. [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
  61. clear params
  62. if nargin < 4 || isempty(fscorr); fscorr=0; end;
  63. if nargout > 7 && err(1)==0;
  64. %Cannot compute error bars if err(1)=0. Need to change params and run again.
  65. error('When errors are desired, err(1) has to be non-zero.');
  66. end;
  67. if nargout > 9 && err(1)~=2;
  68. error('Cerr computed only for Jackknife. Correct inputs and run again');
  69. end;
  70. [N,Ch]=check_consistency(data1,data2);
  71. zerosp=zeros(1,Ch); % intialize the zerosp variable
  72. nfft=max(2^(nextpow2(N)+pad),N);
  73. [f,findx]=getfgrid(Fs,nfft,fpass);
  74. tapers=dpsschk(tapers,N,Fs); % check tapers
  75. J1=mtfftc(data1,tapers,nfft,Fs); % fourier transform of continuous data
  76. [J2,Msp2,Nsp2]=mtfftpb(data2,tapers,nfft); % fourier transform of point process data
  77. zerosp(Nsp2==0)=1; % set the trials where no spikes were found to have zerosp=1
  78. J1=J1(findx,:,:);
  79. J2=J2(findx,:,:);
  80. S12=squeeze(mean(conj(J1).*J2,2));
  81. S1=squeeze(mean(conj(J1).*J1,2));
  82. S2=squeeze(mean(conj(J2).*J2,2));
  83. if trialave; S12=squeeze(mean(S12,2)); S1=squeeze(mean(S1,2)); S2=squeeze(mean(S2,2)); end;
  84. C12=S12./sqrt(S1.*S2);
  85. C=abs(C12);
  86. phi=angle(C12);
  87. if nargout==10;
  88. if fscorr==1;
  89. [confC,phistd,Cerr]=coherr(C,J1,J2,err,trialave,[],Nsp2);
  90. else
  91. [confC,phistd,Cerr]=coherr(C,J1,J2,err,trialave);
  92. end;
  93. elseif nargout==9;
  94. if fscorr==1;
  95. [confC,phistd]=coherr(C,J1,J2,err,trialave,[],Nsp2);
  96. else
  97. [confC,phistd]=coherr(C,J1,J2,err,trialave);
  98. end;
  99. end;
  100. clear Msp2