Nugenta at 19:15, 8 March 2019

2019-03-08T19:15:56Z

← Older revision		Revision as of 15:15, 8 March 2019
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	sam_power applies the beamformer coefficients to the filtered MEG data (specified by ImageBand) to compute the estimated source timeseries. It then applies the Hibert transform to obtain the envelope of power. This is followed by a lowpass filter (specified by SmoothBand) and resampling at the interval specified by TimeStep. The smoothed, resampled Hilbert envelope of power is written out to each voxel.		sam_power applies the beamformer coefficients to the filtered MEG data (specified by ImageBand) to compute the estimated source timeseries. It then applies the Hibert transform to obtain the envelope of power. This is followed by a lowpass filter (specified by SmoothBand) and resampling at the interval specified by TimeStep. The smoothed, resampled Hilbert envelope of power is written out to each voxel.

			==Usage==

			sam_power -r <dataset_name> -m <parameter_file_name> [options]
			The -r flag is followed by the dataset name (with or without the .ds suffix). The -m flag is followed by the parameter file name (with or without .param).

			Other options:

			-v verbose mode
			-h show help

			Required parameters (either in the .param file or on the command line):

			RemoveBaseline: designates which option is used for baseline removal
			CovBand: Bandpass for covariance matrix, also specifies subdirectory for weights
			ImageBand: designates the bandpass for imaging the power
			SmoothBand: designates the lowpass filter for smoothing the Hilbert envelope
			TimeStep: Sampling interval for output image
			ImageMetric: Hilbert is always used
			NumMarkers: must be 0 (zero)
			CovType: must be GLOBAL

			Optional parameters:

			ImageFormat: Designates whether the weights are in +orig or +tlrc space
			ImageDirectory: Directory where the output images are written, default is the SAM directory
			PrefixLength: Number of characters in the MEG dataset name used for naming MRI files.

			==Output Files==

			The output consists of a single 3D+time NIFTI format image, downsampled to the sampling interval specified by TimeStep.

Nugenta: Created page with " Return to Source Localization - SAM ==Description== sam_power computes the Hilbert envelope of power for continuous data and outputs a 3D+tim..."

2019-03-07T22:19:00Z

Created page with " Return to Source Localization - SAM ==Description== sam_power computes the Hilbert envelope of power for continuous data and outputs a 3D+tim..."

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[[Source Localization - SAM | Return to Source Localization - SAM]]

==Description==

sam_power computes the Hilbert envelope of power for continuous data and outputs a 3D+time image. It does not compute event-related power (like [[sam_ers and sam_ersc | sam_ers and sam_ersc]] or [[sam_4d and sam_4dc | sam_4d and sam_4dc]]. sam_power is intended for use in connectivity studies of the correlation of the envelope of power among voxels — e.g., by using ICA or the AFNI function “Instacorr”.

sam_power applies the beamformer coefficients to the filtered MEG data (specified by ImageBand) to compute the estimated source timeseries. It then applies the Hibert transform to obtain the envelope of power. This is followed by a lowpass filter (specified by SmoothBand) and resampling at the interval specified by TimeStep. The smoothed, resampled Hilbert envelope of power is written out to each voxel.

Sam power - Revision history

Nugenta at 19:15, 8 March 2019

Nugenta: Created page with " Return to Source Localization - SAM ==Description== sam_power computes the Hilbert envelope of power for continuous data and outputs a 3D+tim..."