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I am trying to recreate the following results:

Spectrogram

from the following data:

https://www.dropbox.com/s/mi3szqgzgku29rn/FS40.dat

the time is in milliseconds (frequency is 40000 Hz)

The article state that they used Complex Morlet wavelet to create the spectrogram: " Power estimates from the averaged LFPs were calculated from time–frequency spectrograms of the data from 1–88 Hz by convolving the signals with a complex Morlet wavelet of the form

w(t,f0 ) = Aexp(−t^2 / 2*σ^2 )exp(2*iπf0*t)

for each frequency of interest f0, where σ = m/2πf0, and i is the imaginary unit. The normalization factor was A = 1 /(σ (2π)^0.5 ), and the constant m defining the compromise between time and frequency resolution was 7.

I only managed to get some "good" results using spectrogram function in matlab. But I dont have much idea of how to use the morlet complex wavelet. I got bad result when trying to use cwt with 'morl' window

Thank You.

P.S.

I'm trying to recreate this article:

Computational modeling of distinct neocortical oscillations driven by cell-type selective optogenetic drive: separable resonant circuits controlled by low-threshold spiking and fast-spiking interneurons.

Oren
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    Well, I'd say you have been mislead by the wording in the paper. What is shown in the figure is a time-frequency plot of signal energy, but it is not a spectrogram. The latter term is more general, every spectrogram is a time-frequency plot of signal energy, but not vice versa. The `spectrogram` function in Matlab particularly uses a short-time Fourier transform instead of a wavelet transform. Secondly, it is strange to use a complex wavelet if the intention is to estimate spectral energy. – A. Donda Oct 15 '13 at 19:19
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    For doing time-frequency analyses especially of neurophysiological data in Matlab, I'd recommend [FieldTrip](http://fieldtrip.fcdonders.nl/). `ft_freqanalysis` includes an option to use a Morlet wavelet. – A. Donda Oct 15 '13 at 19:20

1 Answers1

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Well I managed to find this MATLAB package

https://sites.google.com/site/rwfwuwx/Home/mfeeg

It does almost the same operation that as been done in the paper..

the related files in the package are: mf_tfcm.m & mf_cmorlet.m

Oren
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