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Statistical analysis and modeling of neural data Lecture 17. Bijan Pesaran 12 November, 2007. Goals. Practical issues of spectral representation Spectral estimation problem Examples on real data. Spectrum. power. Spike times. 1/T. +. power. =. T. Coherency. frequency. High. Low.
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Statistical analysis and modeling of neural dataLecture 17 Bijan Pesaran 12 November, 2007
Goals • Practical issues of spectral representation • Spectral estimation problem • Examples on real data
Spectrum power Spike times 1/T + power = T Coherency frequency High Low Spikes Field Spectral intuition = LFP Voltage
Fundamental concepts • Positive and negative frequency • Nyquist frequency – aliasing • Rayleigh frequency • Spectral density and power K even K odd
The spectral estimation problem Consistency and bias
Example I: LFP spectrograms • Estimation issues • Bias • Narrow band • Broad band • Variance • Degrees of freedom
Example I: LFP spectrograms • Confidence intervals • Chi2 • Assume Gaussian process • Jackknife • Does not assume Gaussian process
Cue Saccade Cue Saccade Example I: LFP spectrograms • Example recording
Multitaper estimate - Single Trial, [5,9] Periodogram – Single Trial Example I: LFP spectrograms
Example I: LFP spectrograms Periodogram – Single Trial Multitaper estimate - Single Trial
Multitaper estimate - Nine Trials [5,9] Example I: LFP spectrograms Multitaper estimate - Single Trial [5,9]
Example I: LFP spectrograms Multitaper estimate - Single Trial Multitaper estimate - Nine Trials
Multitaper estimate - 95% Jackknife Leave-one-out Example I: LFP spectrograms Multitaper estimate - 95% Chi2
Multitaper estimate - T = 0.2s, W = 25Hz Example I: LFP spectrograms Multitaper estimate - T = 0.5s, W = 10Hz
Example II: Spike rates, spectra and coherence Multitaper spectrum [8,15] Auto-correlation fn
Example II: Spike rates, spectra and coherence Multitaper coherence 9 trials, [8,15] Cross-correlation fn
Example II: Spike rates, spectra and coherence Multitaper coherence 9 trials, [8,15] Multitaper coherence 9 trials, [12,23]