Spectrogram and Topographic Map

Spectrogram Parameters:

1. Frequency Pass: Select at which frequency you wish to filter your EEG data by giving two number one next to the other. For example : 10 30 , would filter the EEG data by letting only frequencies greater than 10Hz and frequencies lower than 30 Hz in. The input must be greater than 0 and two number one next to the other are required.
2. Temporal Smoothing Median Filter Order: Select the order of your median filter in order to reduce the noise in the spectrogram.
3. Time-Bandwidth product and Numbers of Tapers: You should generally set the number of tapers to be 2 times the time-bandwidth product − 1, as using more tapers will include tapers with poor concentration in the specified frequency bandwidth (see the Chronux documentation for a more information1).
4. Length of Window: The length of the windows over which the spectrum will be calculated.
5. Step Size: The step at which to move the previously defined window to calculate the spectrogram.
6. 6. Print check box: By selecting print, when the pipeline will have finished computing the spectrogram it will output it as a figure to the screen (fig. 11).
7. Save check box: By selecting save the pipeline will save the file in the Spectrogram and Topographic map folder under a name that reflect the time at which the analysis was performed (fig. 12). Also, a text file containing the input will be saved using the same name as the figure.

Spectrogram Analysis Examples :

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Topographic Map Parameters

1. Frequencies: For the topographic map, you need to enter up to 4 frequencies at which you want to visualize the topographic map. If more frequencies are inputted only the first 4 will be outputted. Only 0.5 increment are allowed, the frequency will be rounded if not written properly. The frequencies allowed range from 0Hz to the sampling rate at which the EEG signal were collected divided by 2 (i.e. Nyquist frequency). Example of correct input: 10Hz 24.5Hz 245Hz 123.5Hz.
2. Print check box: If selected the pipeline will output the topographic map as soon as it is done computing it (fig. 13).
3. Save check box: If selected it will save it in the topographic map folder in the same format as mentioned in figure 12.

Topogaphic Map Analysis Examples :

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