BESA Research ICA - Revision history

Abinash at 13:23, 5 May 2021

2021-05-05T13:23:31Z

Jaehyun: /* ICA Analysis - Main Window */

2019-07-15T09:34:19Z

‎ICA Analysis - Main Window

Jamie: /* Independent Component Analysis */

2019-03-26T14:25:31Z

‎Independent Component Analysis

Jamie: /* ICA Analysis - Main Window */

2019-03-26T14:17:43Z

‎ICA Analysis - Main Window

Jamie: /* ICA Analysis - Main Window */

2019-03-26T14:08:37Z

‎ICA Analysis - Main Window

Jamie: /* Independent Component Analysis */

2019-03-26T13:54:10Z

‎Independent Component Analysis

Jamie: /* ICA Analysis - Main Window */

2019-03-26T13:50:08Z

‎ICA Analysis - Main Window

Jaehyun: /* ICA Analysis - Main Window */

2017-06-02T13:13:03Z

‎ICA Analysis - Main Window

Jaehyun at 12:39, 30 May 2017

2017-05-30T12:39:14Z

Show changes

Alexa at 13:05, 7 April 2017

2017-04-07T13:05:47Z

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 |title = Module information
 |module = BESA Research Basic or higher
-|version = 6.1 or higher
+|version = BESA Research 6.1 or higher
 }}
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 <span style="color:#3366ff;">'''Map Topography '''</span>opens the 3D map of the currently selected ICA component (only one component can be selected for this option). The label of the currently selected ICA component is displayed in the bottom left corner of the mapping window. The function ''"Time-Series-Mapping” ''is deactivated when mapping ICA components as the topography does not change over time. Each map is scaled at 120% of its absolute maximum value.
-The option <span style="color:#3366ff;">'''Define as Artifact Topography'''</span> opens the “''Select Topographies” ''tab of the Artifact Correction Dialog (analogous to pressing ''Artifact / Select''). In this tab, the selected ICA component can be assigned to artifact categories HEOG, VEOG, Blink, EKG, Other1 or Other2. A maximum number of 10 ICA components can be selected at a time when using the artifact categories Other1 and Other2.For the other artifact categories, only 1 ICA component can be selected. &nbsp;After assigning an ICA topography to an artifact category, the topography map and artifact view are shown. Data are not automatically corrected, as this would prompt a new ICA calculation on artifact-corrected data. If the data contain more than one channel type, artifact correction based on ICA components is only available for the channel type on which the ICA was calculated.
+The option <span style="color:#3366ff;">'''Define as Artifact Topography'''</span> opens the “''Select Topographies” ''tab of the Artifact Correction Dialog (analogous to pressing ''Artifact / Select''). In this tab, the selected ICA component can be assigned to artifact categories HEOG, VEOG, Blink, EKG, Other1 or Other2. A maximum number of 10 ICA components can be selected at a time when using the artifact categories Other1 and Other2. For the other artifact categories, only 1 ICA component can be selected. &nbsp;After assigning an ICA topography to an artifact category, the topography map and artifact view are shown. Data are not automatically corrected, as this would prompt a new ICA calculation on artifact-corrected data. If the data contain more than one channel type, artifact correction based on ICA components is only available for the channel type on which the ICA was calculated.
-<span style="color:#3366ff;">'''Send Topography to Source Analysis'''</span> sends all selected ICA topographies to the Source Analysis module as ICA components. This is only possible if the Source Analysis window is open. Within the Source Analysis window the ICA components can be displayed by pressing the ICA button. Right-clicking on an ICA label allows adding the ICA component(s) to the solution as spatial topographies.
+<span style="color:#3366ff;">'''Send Topography to Source Analysis'''</span> sends all selected ICA topographies to the Source Analysis module as ICA components. This is only possible if the Source Analysis window is open. Within the Source Analysis window, the ICA components can be displayed by pressing the ICA button. Right-clicking on an ICA label allows adding the ICA component(s) to the solution as spatial topographies.
 <span style="color:#3366ff;">'''Save Topography'''</span> saves all selected ICA topographies in an ASCII-file. This file can be opened in the Source Analysis window or reloaded with ''Load Components. ''File name and path can be selected in the standard saving dialog. The default name is the basename of the current file with the extension “<span style="color:#ff9c00;">'''<nowiki>*.ica</nowiki>'''</span>”. If the data contain different channel types, the filename will be “*_<span style="color:#ff9c00;">'''channeltype.ica'''</span>” (e.g. “*_<span style="color:#ff9c00;">'''Eeg.ica'''</span>”). The format of <span style="color:#ff9c00;">'''<nowiki>*.ica</nowiki>'''</span> files is similar to artifact topography files (<span style="color:#ff9c00;">'''<nowiki>*.atf</nowiki>'''</span>). The first line contains the number of elements (channels) per ICA component (Nchan). The second line contains a list of channel labels and the channel type (Type). The following lines contain the ICA topographies, one topography per line. Each line begins with the corresponding ICA label. Please note that ICA topographies are not average referenced!
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 '''Switch off / on ICA component(s)'''
-Selected ICA components are ignored in the Source Analysis window. Their labels and waveforms are grayed out. If data are sorted by the channel order, un-selected ICA components are automatically sorted to the bottom of the waveform panel. This can be helpful when many ICA components are sent to or loaded in the Source Analysis window. Un-selected ICA-components can be switched back on.
+Selected ICA components are ignored in the Source Analysis window. Their labels and waveforms are greyed out. If data are sorted by the channel order, un-selected ICA components are automatically sorted to the bottom of the waveform panel. This can be helpful when many ICA components are sent to or loaded in the Source Analysis window. Un-selected ICA-components can be switched back on.
 '''Add selected / all ICA components to solution'''
-One spatial component, corresponding to one ICA topography, per selected ICA label is added to the source solution. The absolute position of the displayed dipoles should not be interpreted as an accurate location, as it is located at the center of gravity of the according map. The source waveform associated with the spatial component is displayed in the Source Waveform panel in the middle of the Source Analysis window. Spatial components are the preferable choice for modeling artifact topographies in
+One spatial component, corresponding to one ICA topography, per selected ICA label is added to the source solution. The absolute position of the displayed dipoles should not be interpreted as an accurate location, as it is located at the center of gravity of the according map. The source waveform associated with the spatial component is displayed in the Source Waveform panel in the middle of the Source Analysis window. Spatial components are the preferable choice for modelling artifact topographies in
 a source solution (rather than performing source analysis on artifact-corrected data). Spatial components can also be useful if parts of the signal are to be explained that are not of primary interest to the research question in order to reduce the amount of variance that needs to be explained by discrete source analysis.

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 <!-- [[Image:ICA (1).jpg]] -->
-[[Image:ICA_Analysis1a.png]]
+[[Image:ICA_Analysis1a.png|600px]]
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-[[Image:ica2.png]]
+[[Image:ica2.png|300px]]
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-[[Image:ica3.png]]
+[[Image:ica3.png|300px]]
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-[[Image:ica4.png]]
+[[Image:ica4.png|600px]]
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-[[Image:ica5.png]]
+[[Image:ica5.png|600px]]
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 <span style="color:#3366ff;">'''Export ICA Reconstructed Data Without Selected Components'''</span>: <span style="color:#3366ff;">'''Whole File'''</span> creates a new dataset '''without''' the selected ICA components and with the current filter settings of the '''entire dataset'''.
 [[Image:ica6.png]]
 === ICA Analysis - Source Analysis Window ===

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-[[Image:ICA3.png]]
+[[Image:ica3.png]]
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-[[Image:ICA (3).gif ]]
+[[Image:ica4.png]]
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-[[Image:ICA (4).gif ]]
+[[Image:ica5.png]]
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-[[Image:ICA (5).gif ]]
+[[Image:ica6.png]]
 === ICA Analysis - Source Analysis Window ===
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-[[Image:ICA (6).gif|400px]]
+[[Image:ica7.png]]
 ''Figure 1''

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-<!-- [[Image:ICA (1).gif|400px]] -->
+[[Image:ica2.png]]
-[[Image:ICA_(1)_BR6_1.png]]
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-<!-- [[Image:ICA (2).gif|400px]] -->
+[[Image:ICA3.png]]
-[[Image:ICA_(2)_BR6_1.png]]

← Older revision		Revision as of 14:08, 26 March 2019
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	Before ICA is calculated, the dimensionality of data is optionally reduced by PCA. By default, all PCA components are ignored that explain less than 1% variance. The use of PCA can be switched off or the variance cutoff can be altered by pressing <span style="color:#3366ff;">'''ICA / Options'''</span>.		Before ICA is calculated, the dimensionality of data is optionally reduced by PCA. By default, all PCA components are ignored that explain less than 1% variance. The use of PCA can be switched off or the variance cutoff can be altered by pressing <span style="color:#3366ff;">'''ICA / Options'''</span>.
		+
		+	* '''Extended Infomax algorithm''' is based on the maximization of entropy and presents a natural gradient form for the independent components computation.
		+	** Lee TW et al. Independent component analysis using an extended infomax algorithm for mixed sub-Gaussian and super-Gaussian sources. Neural Computation, 11(2), 1999, 409-433
		+	*'''Second-order blind identification (SOBI)''' algorithm relies on second-order statistics that takes advantage of temporal correlations in the source activities.
		+	**Belouchrani A et al. A blind source separation technique using second-order statistics. IEEE Transactions on Signal Processing, 45(2), 1997, 434-444

← Older revision		Revision as of 13:54, 26 March 2019
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	In case EEG and MEG data are both available, ICA analysis will only run on the data type that is selected by the EEG/MEG button. Running ICA on combined gradiometer/magnetometer data is not possible. It can only run on one channel type at a time.		In case EEG and MEG data are both available, ICA analysis will only run on the data type that is selected by the EEG/MEG button. Running ICA on combined gradiometer/magnetometer data is not possible. It can only run on one channel type at a time.

−	The method behind ICA analysis is the extended ICA algorithm (Lee TW et al. Independent component analysis using an extended infomax algorithm for mixed sub-Gaussian and super-Gaussian sources. Neural Computation 11(2), 1999, 409-433). Before ICA is calculated, the dimensionality of data is optionally reduced by PCA. By default, all PCA components are ignored that explain less than 1% variance. The use of PCA can be switched off or the variance cutoff can be altered by pressing <span style="color:#3366ff;">'''ICA / Options'''</span>.	+	Before ICA is calculated, the dimensionality of data is optionally reduced by PCA. By default, all PCA components are ignored that explain less than 1% variance. The use of PCA can be switched off or the variance cutoff can be altered by pressing <span style="color:#3366ff;">'''ICA / Options'''</span>.

← Older revision		Revision as of 13:50, 26 March 2019
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	<!-- [[Image:ICA (1).jpg]] -->		<!-- [[Image:ICA (1).jpg]] -->
−	[[Image:~~ICA_(1)_jpg_BR6_1~~.png~~\|600px~~]]	+	[[Image:ICA_Analysis1a.png]]

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 |version = 6.1 or higher
 }}
 ==  <span style="color:#3366ff;"><span style="color:#00000a;">Independent Component Analysis</span></span> ==