Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_spiketriggeredspectrum_fft”.

  FT_SPIKETRIGGEREDSPECTRUM_FFT computes the Fourier spectrum (amplitude and phase)
  of the LFP around the % spikes.  A phase of zero corresponds to the spike being on
  the peak of the LFP oscillation. A phase of 180 degree corresponds to the spike being
  in the through of the oscillation. A phase of 45 degrees corresponds to the spike
  being just after the peak in the LFP.
  If the triggered spike leads a spike in another channel, then the angle of the Fourier
  spectrum of that other channel will be negative. Earlier phases are in clockwise
  Use as
    [sts] = ft_spiketriggeredspectrum_convol(cfg,data,spike)
    [sts] = ft_spiketriggeredspectrum_convol(cfg,data)
  where the spike data can either be contained in the DATA input or in the SPIKE input.
  The input DATA should be organised as the raw datatype, obtained from FT_PREPROCESSING
  The (optional) input SPIKE should be organised as the spike or the raw datatype,
  obtained from FT_SPIKE_MAKETRIALS or FT_PREPROCESSING (in that case, conversion is done
  within the function)
  Important is that data.time and spike.trialtime should be referenced relative to the
  same trial trigger times.
  The configuration should be according to
    cfg.timwin       = [begin end], time around each spike (default = [-0.1 0.1])
    cfg.foilim       = [begin end], frequency band of interest (default = [0 150])
    cfg.taper        = 'dpss', 'hanning' or many others, see WINDOW (default = 'hanning')
    cfg.tapsmofrq    = number, the amount of spectral smoothing through
                       multi-tapering. Note that 4 Hz smoothing means plus-minus 4 Hz,
                       i.e. a 8 Hz smoothing box. Note: multitapering rotates phases (no
                       problem for consistency)
    cfg.spikechannel = string, name of spike channels to trigger on = Nx1
                       cell-array with selection of channels (default = 'all'),
                       see FT_CHANNELSELECTION for details     = 'no', 'text', 'textbar', 'gui' (default = 'no')
  The output STS data structure can be input to FT_SPIKETRIGGEREDSPECTRUM_STAT
  This function uses a NaN-aware spectral estimation technique, which will default to the
  standard Matlab FFT routine if no NaNs are present. The fft_along_rows subfunction below
  demonstrates the expected function behaviour.
  See FT_SPIKETRIGGEREDINTERPOLATION to remove segments of LFP around spikes.
  See FT_SPIKETRIGGEREDSPECTRUM_CONVOL for an alternative implementation based
  on convolution