1. File
1.1 New
This command is not available. The new file is created only upon the actual measurement by
using “MEG measurement” command described in Section 2.7.
1.2 Open...
The dialog to choose the MEG file to be opened will appear. The MEG file is specified by the
extensions, which are defined in the Measurement Options dialog described in Section 2.8.
1.3 Transfer...
This command transfers the files recorded in “transfer suspended mode” from the DAQ PCs
to the main PC. The dialog to choose the file to be transferred will appear after selecting the
command. If the size of the recorded data file is too large, the time to transfer the data from
each DAQ PC to the main PC becomes very long and interrupt the smooth test. In that case,
the user can select “transfer suspended mode” upon starting the recording.
When the data files are recorded with transfer suspended mode, they are stored on the hard drives of each DAQ PC. These files must be transferred to the main PC before analysis.
When the user would like to transfer the data files all at once, not one by one, use
“Suspended file list” command described in Section 1.4.
1.4 Suspended File List
The dialog to show the suspended file list will appear. The user can see the list of the files
which have not been transferred yet. The files to be transferred can be chosen from the list.
This command transfers multiple files all at once.
1.5 Save
The modification on a data file is overwritten by this command.
1.6 Save As...
The data file is saved as the new file.
1.7 Close
This command closes the file. If the modification of the data file has not been saved yet, the
dialog asking if it should be saved or not will appear.
1.8 Close All
This command closes all opened files. If there are the data files which have not been saved
yet, the dialogs asking if the modification should be saved or not will appear for each file.
1.9 Pack MEG file
This command compresses the raw data file in order to save space on the hard drive. This
command cannot be applied on the averaged data file. The compressed (packed) file cannot
be opened until expanded (unpacked).
1.10 Unpack MEG file
This command expands the compressed raw data file.
1.11 Grand Average
This command creates a new data file of the grand average between the multiple data files.
The dialog to choose the data files will appear. The user can choose the multiple data files to
be averaged at once on the dialog. The sampling rate and the data length of all the data files
to be averaged must be identical.
After choosing the data files, the dialog to set the filename of the grand average data file will
appear.
1.12 Export
The data on the MEG data file can be exported to other applications as general binary or ascii
files. The file format of the binary/ascii file, the exported channels, and the temporal region
to be exported are also selectable. If the data is exported as an ascii file, the unit of the values
are also selectable. After setting the file format, the dialog to set the filename of the exported
data file will appear.
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1.13 Import
The data from the other application can be imported to the MEG data file. The imported data
file must have the same format as the exported data file by the “Export” command. The file
format, the channels, the temporal region, and the unit for the ascii file are selectable as seen
with the “Export” command. The imported data will overwrite the existing data on the MEG
data file.
1.14 Block Export
If there are several MEG files whose data should be exported as general binary or ascii files,
the user does not need to repeat the same procedure many times with this command. The
dialog to choose which files should be exported will appear. Then all of the selected data files
will be exported in the same format at once. The directory of the exported files is the same as
the original data files. The filename of the exported data files is decided automatically for
each one. It is the same as the original filename but the extension is changed to the specific
one of the file format.
to export the raw data in binary format, the Units should be set
to A/D; to export the data in Tesla, the Units for the MEG
channels should be set to Tesla. If the users are exporting non
MEG channels, and want them not in binary, then set Other
channels to Volts.
The file type for raw files may be 16-
bit or 32-bit integer (if the users are
using A/D units) or 64-bit real (=64
bit floating point/binary/double
format): averaged files should
always be exported as 64-bit real.
Select the necessary sensors (e.g. 0 to 160) (see Selecting
Channels below) and export them ONLY by pressing “Selected
Channels,” or export every channel by pressing “All channel”
Start time and End time are
determined by the users, and
are listed in milliseconds. The
length of the file should
already be set as default.
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1.15 Navigator File
The imported MR slice image can be saved as the set of the bitmap image files by commands
in this category. The bitmap file is the general image file format of Windows, whose file
extension is “.bmp”.
1.15.1 Axial View
The dialog to set the filename and the directory for the exported image files. The series of the
image files of the axial view of the MRI slices can be saved. The number of the slice is
attached to the filename of each image file automatically.
1.15.2 Coronal View
The dialog to set the filename and the directory for the exported image files. The series of the
image files of the coronal view of the MRI slices can be saved. The number of the slice is
attached to the filename of each image file automatically.
1.15.3 Sagittal View
The dialog to set the filename and the directory for the exported image files. The series of the
image files of the sagittal view of the MRI slices can be saved. The number of the slice is
attached to the filename of each image file automatically.
1.16 BESA Export
BESA (Brain Electrical Source Analysis) is the widely used software for source analysis and
dipole localization in EEG and MEG research. The commands of this category are
responsible for exporting the data of the MEG file to BESA format. Before using the
commands in this directory, the matching process between the MRI and the MEG
coordination systems should first be finished.
1.16.1 Electrode Configuration
The information of electrode configuration is exported to a text file with the extension of
*.ela.
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1.16.2 Position File
The information of the position and direction of each sensor are exported to a text file with
the extension of *.pos.
1.16.3 ASCII Data
The temporal waveform data of every channel is exported to a text file with the extension of
*.asc.
1.16.4 Surface Point File
The dialog to pick up the preauricular, nasion, and 15 points on the surface of the head from
the MRI data will open. The positions of the picked-up points is exported to a text file with
the extension of *.sfp
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1.17 MRI File
Meg Laboratory can treat the MRI data only transformed to the specific format. These
commands transform the general formats of the MRI data files to the Meg Laboratory MRI
data file format with the extension of *.mri.
1.17.1 Create MRI File from DICOM-3 file
The dialog to select the set of the DICOM files of the MRI data will appear. The selected files
are combined and transformed to a single file in the Meg Laboratory MRI format. The
extension of the transformed file is *.mri. After choosing from the set of the original data files
in DICOM format, the dialog to name the created MRI data file will appear.
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1.17.2 Create MRI File from pixel data
The dialog to create the Meg Laboratory MRI data format file from the set of the general
image files will appear. To make the MRI data file created by this command equivalent to the
file from the DICOM format file, it is necessary to input the information of the patient, the
binary format of the original data files, slice features of the set of the original files, the pitch
of the pixels, etc. After setting the parameters in this dialog, another dialog to name the
created MRI data file will appear.
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1.17.3 Create MRI File from digitizer data
This command creates the MRI data file in Meg Laboratory MRI data file format with the
extension of *.mri from the EMSI data files acquired by the 3D digitizer of Polhemus, such as
FASTRAK or ISOTRAK. The dialog to input the patient information and to select the
filename of head shape file and marker coil file from EMSI and to assign the coordination
system will appear. The head shape file and the marker coil file have the extensions of *.hsp
and *.elp, respectively. After setting all the parameters, the dialog to name the created MRI
data file will appear.
Load the head shape file.
The preview of the head shape described
by dots will appear here.
Load the marker coil file.
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1.17.4 Setup Head Coordinate System
This command assigns the head coordination system to the existing MRI data file in Meg
Laboratory format. The dialog to select the MRI data files in Meg Laboratory format will
appear. After choosing the filename of the MRI data file, the dialog to set the coordination
system will be opened. The information of the coordination is attached to the MRI data file
upon clicking the OK button in the dialog.
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1.18 MEG Marker Positioning
The dialog to estimate the positions of the MEG marker coils will appear. Another dialog to
choose the marker coil measurement file will be opened upon clicking the Search button.
After selecting the marker coil measurement file, the estimation starts upon clicking the
Execute button. The result of the estimation is graphically shown on the dialog. Once the
estimation is executed with a certain file, the result is stored in the file automatically. Load
button can call the previously estimated result and the user doesn’t need to execute the second
estimation.
If the users have more than one marker coil measurement file for the same session, the users
may compare values. Press the Compare button. The users will be asked to load the second
file. The differences between the localizations will be presented numerically and may also be
presented graphically. If the answer is “yes” to the display, circles will represent the
first/current file, and crosses will represent the second file.
1) Make sure the estimation
parameters are correct. Number of
Markers should match the number
of working sensors. Reference
Channel is not used. Averaging
Count should be 16. Trigger
Threshold should be around 160.
2) Execute the localization
command.
3) Review the results of the localization. In
particular, examine the GOF (goodness of fit) of the
estimations (these should ideally be above 99%).
The locations of the coils are displayed in those
three directions.
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1.19 Print...
The general print dialog will appear. The screen shot of the window of Meg Laboratory can
be printed by this command.
1.20 Print Preview
The general print preview window will appear and the user can confirm the result of the
printing on the screen.
1.21 Print Setup...
The general print setup dialog will appear.
1.22 Exit
Every MEG data file will be closed and Meg Laboratory is exited.
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2. Acquis
If the PC on which Meg Laboratory installed doesn’t have the connection to the DAQ PCs
and SQUID electronics, this menu option will not appear/exist.
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2.1 System Definition
2.1.1 System Scale
The System Scale Setup dialog will appear. Here, the user can set the number of the DAQ
PCs, the number of A/D boards installed on each DAQ PC, the number of the channels on an
A/D board, and the number of the SQUID electronics.
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2.1.2 Channel Definition
The channel definition dialog will appear. The user can check or modify the type, position,
and direction of each sensor and assign the names to the optional channels on the dialog.
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2.2 Auto Tuning Setup
Usually, this command is only used upon the initial installation process or in the regular
maintenance process. The user must not use without the advices of the service support.
The dialog to set the mode of the auto-tuning and the parameters for tuning will appear. There
two modes of the auto-tuning: Full-tuning and Voffset-tuning. Full-tuning adjusts the two
parameters of the SQUID sensors: bias current and offset voltage. Voffset-tuning adjusts
only the offset voltage.
2.3 Auto Tuning
The command tunes the parameters of all the SQUID sensors automatically. Before the MEG
measurement, the user must execute this command.
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2.4 Manual Tuning
Usually, this command is only used upon the initial installation process or in the regular
maintenance process. The user must NOT use without the advice of the service support.
The SQUID electronics are fully controlled directly on the dialog.
2.5 DC offset Tuning
This command is not implemented.
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2.6 File
Usually, the commands in this category are only used upon the initial installation process or
in the regular maintenance process. The user must NOT use without the advice of the service
support.
The two parameters of the SQUID sensors, bias current and offset voltage, can be saved to a
file and loaded from the file by the commands in this category.
2.6.1 Load
The settings of the two parameters of the SQUID sensors (bias current and offset voltage) are
stored in a file and thus can be called and set to the SQUID electronics by this command. The
dialog to select the file to be opened will appear.
2.6.2 Save As
The current settings of the two parameters of the SQUID sensors (bias current and offset
voltage) can be saved to a file by this command. The dialog to name the file to be saved will
appear.
2.6.3 Load Init File
This command enables the user to reset the initial settings for the two parameters of the
SQUID sensors (bias current and offset voltage) back to their initial state which was stored by
the command Save Init File.
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2.6.4 Save Init File
The current settings for the two parameters of the SQUID sensors (bias current and offset
voltage) can be saved as an initial state. To recall the initial state, the command Load Init File
should be executed.
2.6.5 Save As Text File
To analyze the parameters of the SQUID sensors (bias current and offset voltage) this
command exports the current settings of the parameters to a text file.
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2.7 MEG Measurement
The dialog controlling the DAQ PCs and the SQUID electronics will appear. Every recording
of data is executed in this dialog.
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2.8 Options
The Measurement Options dialog will appear. The user can choose the behavior of the
SQUID electronics upon launching Meg Laboratory on the dialog. The settings for the default
file extension of the MEG data files in every mode can be changed, but this is NOT
recommended. Other trivial settings relating to data acquisition can be changed in this dialog.
2.9 Control Panel
This command is not available.
2.10 ReBoot DAQ
This command reboots all the DAQ PCs remotely.
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2.11 Shutdown DAQ
This command shuts-down all the DAQ PCs remotely.
2.12 Maintenance
2.12.1 Abort DAQ
The command forces a termination of the software for the real time monitors on each DAQ
PC.
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3. Edit
This menu appears only when MEG data files are opened.
3.1 Undo
The command removes the effect of the previous command in the category of Edit and
returns the data to the previous state. When this command is executed, the dialog confirming
the operation will appear.
3.2 Cut
This command is not available for this version.
3.3 Copy
This command is not available for this version.
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3.4 Paste
This command is not available for this version.
3.5 Comment
The user can input comments for the data file. The history of the comments is also preserved.
The comments can be imported from other MEG data files.
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3.6 Patient Info
The user can input or modify the information of the patient. The information can be imported
from other MEG data files or MRI data files.
3.7 Channel Info
The channel definition dialog will appear. The user can check or modify the type, position,
and direction of each sensor and assign names to optional channels in the dialog.
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3.8 Macro Command
The Macro command dialog will appear. The user can define a sequence of the commands in
the Edit category; which is frequently used as a macro. The defined macro can be executed in
the dialog. The commands that can be used in a macro are: HPF, LPF, BPF, BEF, Customized
Filter, Moving Averaging, Baseline Correct, Absolute, Multiply, Power, and Channel Math.
Operation.
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3.9 HPF
The High Pass Filter dialog will appear. The user can set: the cut-off frequency of the filter,
window type, width of the digital filter, and the specific channels to be filtered. The frequency
response of the filter can be checked graphically.
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3.10 LPF
The Low Pass Filter dialog will appear. The user can set: the cut-off frequency of the filter,
window type, width of the digital filter, and the channels to be filtered. The frequency
response of the filter can be checked graphically.
3.11 BPF
The Band Pass Filter dialog will appear. The user can set: the cut-off frequency of the filter,
window type, width of the digital filter, and the channels to be filtered. The frequency
response of the filter can be checked graphically.
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3.12 BEF
The Band Elimination Filter dialog will appear. The user can set: the cut-off frequency of the
filter, window type, width of the digital filter, and the channels to be filtered. The frequency
response of the filter can be checked graphically.
3.13 Customized Filter
The user can apply the original FIR filter to the data by this command. The filter should first
be defined in text file format.
The filter is expressed by the following formula.
€
y(n) = x(n - k)h(k)
k= 0
N-1
∑
where x and y are input and output of the filter, respectively, h is the transfer function. h
determines the characteristics of the filter.
3.14 Moving Average
The Moving Average dialog will appear. The point width, method of calculation of average,
and the specific channels applied moving average can be selected in this dialog.
The software can apply moving average to the digitized signals to smoothen out the signal’s
fluctuation. Given a sequence {ai}N
i=1, an n-moving average is a new sequence {si}N-n+1
i=1
defined from the ai by taking the average of subsequence of n terms,
€
si = 1
n
a j .
j= i
i+n-1
∑
So the sequence Sn giving n-moving averages are
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€
S2 = 1
2
(a1 + a2, a2 + a3,..., an-1 + an )
€
S3 = 1
3
(a1 + a2 + a3, a2 + a3 + a4 ,..., an-2 + an-1 + an )
and so on.
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3.15 Baseline Correct
The Baseline correct dialog will appear. This command corrects the difference in the offset of
each channel by subtracting the average value for a certain time period from the sum of the
original signal. The time region for the calculation of the average and optional functions can
be selected in this dialog.
The user can apply slope adjustment to compensate the linearly increasing/decreasing
tendency of the digitized signal. This function is called slope fit. The algorithm of the slope
adjustment approximate the signal by a linear function and then subtract the linear function
from the original signal.
If the measured signal is contaminated by periodical noise, the software can remove the noise
using the ‘noise template’ technique.
3.16 Absolute
This command calculates the absolute value of the data for each channel at every time slice
and replaces the results of the original signal. The Mathematical Operation: Absolute dialog
will appear and the user can select whether all the channels should be applied to the
calculation or only selected channels.
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3.17 Multiply
This command multiplies a given value of the data for each channel at every time slice. The
results of the calculation will replace the original data. The Mathematical Operation: Multiply
dialog will appear and the user can select either all the channels to be calculated/multiplied or
only selected channels.
3.18 Power
This command calculates certain values to the Nth power to the values at every time slice of
each channel. The Mathematical Operation: Power dialog will appear. N will be the given
value to be multiplied. The user can select either all the channels to be multiplied or only
selected channels.
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3.19 Channel Math. Operation
The commands in this category calculate operations between data of multiple channels and
then overwrite the existing data of a channel with the result of the calculations.
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3.19.1 Maximum
This command compares the values of the selected channels at every time slice and creates a
new waveform by extracting the maximum value. The unit of measurement for the data can
also be selected as either A/D or Tesla. This means that the user can select whether the data
should be calibrated before operation, or not. The channels to be calculated and the
overwritten channels can be selected as either Source Channel or Target Channel,
respectively.
3.19.2 Minimum
This command compares the values of the selected channels at every time slice and creates a
new waveform by extracting the minimum value. The unit of measurement for the data can
also be selected as either A/D or Tesla. This means that the user can select whether the data
should be calibrated before operation, or not. The channels to be calculated and the
overwritten channels can be selected as either Source Channel or Target Channel,
respectively.
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3.19.3 Average
This command calculates the average values of the selected channels at every time slice and
creates a new waveform. The unit of the data can be calculated in either A/D or Tesla. This
means that the user can select whether the data should be calibrated before operation, or not.
The channels to be calculated and the overwritten channels can be selected as either Source
Channel or Target Channel, respectively.
3.19.4 Weighted Average
This command calculates the weighted average of all the channels at every time slice and
overwrites the data with the result. A text file which has a list of the weight coefficients
(which we call Weight File) should be prepared before executing the command. The Weight
File and the overwritten channels are selected in the dialog. The unit of measurement for the
data can be selected as either A/D or Tesla. This means that the user can select whether the
data should be calibrated before operation, or not.
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3.19.5 RMS
This command calculates the Route Mean Square of a specific set of the channels at every
time slice and overwrites the data with the result. The channels to be calculated and the
overwritten channels can be selected as either Source Channel or Target Channel,
respectively.
3.20 File Math. Operation
The commands in this category calculate between the active file and the other files. The result
overwrites the active file.
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3.20.1 Add
The data from a certain file is added to the data in the active file one channel at a time. The
result of the addition overwrites the active file. The user can then select the file and the
channels to be added. The sampling rate, data length, and number of the channels should be
identical between the two files.
3.20.2 Subtract
The data from a certain file is subtracted from the data in the active file one channel at a time.
The result of the subtraction overwrites the active file. The user can then select the file and
the channels to be subtracted. The sampling rate, data length, and number of the channels
should be identical between the two files.
3.20.3 Concatenate
The data from a certain file is linked with the data in the active file. The user can then select
the file and the channels to be concatenated. The two files must have the same number of
channels and have been recorded at the same sampling rate.
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3.21 Extract
The data can be cut out between two given time slices. Start time and End time can be set in
the dialog. The data in the unselected region will be lost.
3.22 Thin out
This command reduces the sampling point in the data. The data will be extracted only at
every “x” time slice – where “x” is the given value for Thinout Count. The data at the nonextracted
time slices will be lost.
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3.23 Patch
This command interpolates the data between two time slices by a linear patch or a spline
patch. The Temporal Patch dialog will appear. The user can set the region and the channels to
be patched and then select the patch type on the dialog.
3.24 Forward Problem
The existing data of each channel at the selected time slice will be replaced by the theoretical
magnetic field calculated from the estimated current dipoles at that moment. This command is
selectable only when the user picks the time slice at which the estimated dipoles are
registered. The calculation of the theoretical magnetic field distribution from the electric
current is called forward problem of electromagnetism. On the other hand, pursuing the
electric current distribution based on the observed magnetic field is called inverse problem of
electromagnetism.
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3.25 Noise Reduction
The Noise Reduction using Reference Channels command will appear upon selecting this
command. This only applies if the system is equipped with the magnetic sensors for the
environmental magnetic noise. In addition, these signals along with the MEG signals need to
be acquired. The noise contaminating the MEG signals can be reduced using the signals from
the circumstance for the reference.
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3.26 Averaging
The data recorded in the continuous mode or in the evoked mode with raw data can be
applied in the offline averaging operation.
Two dialogs, Offline Averaging [Main] and Offline Averaging [Trigger List], will appear.
This command can only be selected if the data from the active file has not been averaged.
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4. MRI
Meg Laboratory needs the image data that shows the morphology of the brain for the
investigation of the magnetic source. The image data is mainly provided by an MRI system.
All commands in this category treat the morphological data from MRI systems as the
magnetic source estimation.
4.1 Create MRI File from DICOM-3 file
The dialog to select the set of the DICOM files of the MRI data will appear. The selected files
are combined and transformed to a single file in the Meg Laboratory MRI format. The
extension of the transformed file is *.mri. After choosing the set of the original data files in
DICOM format, the dialog to name the created MRI data file will appear.
4.2 Create MRI File from pixel data
The dialog to create the Meg Laboratory MRI data format file from the set of the general
image files will appear. To make the MRI data file (created by this command equivalent to the
file from the DICOM format file), it is necessary to input the information of the patient, the
binary format of the original data files, slice features of the set of the original files, the pitch
of the pixels, etc. After setting the parameters in the dialog, the dialog to name the created
MRI data file will appear.
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4.3 Create MRI File from digitizer data
This command creates an MRI data file in Meg Laboratory MRI data file format with the
extension of *.mri from the EMSI data files acquired by the 3D digitizer of Polhemus, such as
FASTRAK or ISOTRAK. The dialog to input the patient information, select the filename of
head shape file and marker coil file from EMSI, and assign the coordination system will
appear. The head shape file and the marker coil file have the extensions of *.hsp and *.elp,
respectively. After setting the parameters, the dialog to name the created MRI data file will
appear.
4.4 Setup Head Coordinate System
This command assigns the head coordination system to the existing MRI data file in Meg
Laboratory format. The dialog to select the MRI data files in Meg Laboratory format will
appear. After choosing the filename of the MRI data file, the dialog to set the coordination
system will be opened. The information of the coordination is attached to the MRI data file
upon clicking OK button on the dialog.
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4.5 MRI Filename
This command creates a link between the active MEG data file and the MRI data file created
by one of the commands described in previous sections. The Open MRI file dialog will
appear. Next, select the MRI data file of the corresponding subject to the active MEG data file.
After selecting the MRI data file, the dialog to confirm the subject’s name and ID will appear
before opening the MRI file.
If the user doesn’t have the MRI data of the corresponding subject to the active MEG data file,
the virtual MRI data can NOT be selected.
Once the link between the MEG and MRI data file has been created, the file path from the
MEG data file to the MRI data file is stored in the MEG file. The user doesn’t need to make
the link more than once, unless the relative location of the MRI file is changed.
The option of Without MRI can be selected, if the user wants to delete the link.
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4.6 Pick MRI Marker
The MRI Operation dialog will appear upon executing this command. The user can pick up
the position of the MRI Markers and confirm the assigned positions.
Once this command is executed for a certain MRI data file, the information about the
positions of the markers is stored in the MRI data file automatically. The user doesn’t need to
assign the locations more than once.
If the MRI data file is not linked to the active MEG file, this command cannot be selected.
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4.7 MEG Marker Positioning
The dialog to estimate the positions of the MEG marker coils will appear. Another dialog to
choose the marker coil measurement file will also open. After selecting the marker coil
measurement file, the estimation starts upon clicking Execute button. The result of the
estimation is graphically shown on the dialog. Once the estimation is executed with a certain
file, the result is stored in the file automatically. Load button can call the previously estimated
result and the user doesn’t need to execute the second estimation.
4.8 MRI-MEG Matching
This command can be selected after assigning the position of the MRI markers and estimating
the positions of the MEG markers. The MRI Operation dialog will appear upon executing this
command. The MEG coordination system and the MRI coordination system will be matched
upon clicking the Do Matching button and the error between two systems will then be
displayed. The markers to be used for matching can also be selected by the user in the dialog.
Basically, all five markers should be used for matching.
1) If any of the marker coils are not to be used,
deselect them (uncheck the box next to it).
2) Then press the Do
Matching button.
3) The results of the matching will be displayed, along with
the error around each marker. If any of the coils shows an
excessive error, deselect it and perform the matching again.
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5. Analysis
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5.1 Sphere Model
The source analysis by Meg Laboratory assumes that the brain is a spherical conduction. The
dialog to fit a sphere to the brain graphically will appear. The user can assign a spherical
model to the brain automatically in the dialog. Manual assignment is also available. The
position and the size of the sphere can be adjusted by drawing a circle over the MR image, or
by numerical input.
Once this command is executed for a certain MRI data file, the information about the
spherical model is stored in the MRI data file automatically. The user doesn’t need to assign
the sphere again.
If the MRI data file is not linked to the active MEG file, this command cannot be selected.
A circle is drawn by
dragging over the
MRI image.
The parameters of the sphere can be
adjusted numerically.
The sphere is determined
by clicking this button.
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5.2 Dipole Fitting
After the active MEG data file is linked to the MRI data file and both of the coordination
systems of MRI and MEG are matched to each other and the spherical model is assigned to
the MRI data, this command is selectable.
The dialog to fit one or two theoretical current dipoles to the observed magnetic field
distribution at the selected time slices will appear upon selecting this command (for multiple
dipoles, or more than two dipoles, use the Multi Dipole Fitting command which functions the
same as Dipole Fitting).
Displays the channels currently
being used for dipole fitting
Choose a single time slice, or a series (to select a series,
SHIFT-click and draw a box on the waveform viewer
over the time period). If a series is chosen, all dipoles
after the first are localized starting from the previous
location, rather than randomly.
Fitting Parameters:
• Moving dipole (location, orientation, and intensity can
vary)
• Fixed dipole (orientation and intensity can vary)
• Moment Free dipole (intensity can vary)
Initialization:
• Random,
• Closest Entry (starting point is from the latency with a
dipole – Note, if a series is fit, all time points but the first
operates as Closest Entry),
• Manual Set – select a starting point manually on the MR
image.
Once a dipole has been fit,
GOF, location, orientation,
and intensity information is
filled in.
Used for bilateral dipoles
(e.g. auditory response).
First, localize response in
one hemisphere. Then,
localize response in the
other hemisphere. Select all
MEG channels, check the
“bilateral” option, and
“Estimate” again.
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5.3 Multi Dipole Fitting
After the active MEG data file is linked to the MRI data file and both of the coordination
systems of MRI and MEG are matched to each other and the spherical model is assigned to
the MRI data, this command is selectable.
The dialog to fit one or more theoretical current dipoles to the observed magnetic field
distribution at the selected time slices will appear upon selecting this command.
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5.4 Lead Field Reconstruction
After the active MEG data file is linked to the MRI data file and both of the coordination
systems of MRI and MEG are matched to each other and the spherical model is assigned to
the MRI data, this command is selectable.
The dialog to construct the current dipole array by the lead field method on the specific plane
will appear upon selecting this command.
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5.5 Manual Dipole Fitting
After the active MEG data file is linked to the MRI data file and both of the coordination
systems of MRI and MEG are matched to each other and the spherical model is assigned to
the MRI data, this command is selectable.
The user can define the theoretical current dipoles manually in the dialog which appears upon
selecting this command.
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5.6 Arrange MSI Entries
The theoretical current dipoles estimated by the commands described in the previous sections
are registered in the MSI list. The commands in this category sort the registered magnetic
sources at a specific time slice in the specific order.
5.6.1 Right to Left
The magnetic source entries are sorted by the spatial positions from right to left from the view
point of the subject.
5.6.2 Left to Right
The magnetic source entries are sorted by the spatial positions from left to right from the view
point of the subject.
5.6.3 Anterior to Posterior
The magnetic source entries are sorted by the spatial positions from subject’s anterior to
posterior.
5.6.4 Posterior to Anterior
The magnetic source entries are sorted by the spatial positions from subject’s posterior to
anterior.
5.6.5 Superior to Inferior
The magnetic source entries are sorted by the spatial positions from subject’s superior to
inferior.
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5.6.6 Inferior to Superior
The magnetic source entries are sorted by the spatial positions from subject’s inferior to
superior.
5.6.7 by Intensity in descending order(+)
The magnetic source entries are sorted by the intensity of the dipole in descending order.
5.6.8 by Intensity in ascending order (-)
The magnetic source entries are sorted by the intensity of the dipole in ascending order.
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5.7 Medical Opinion
The user can make notes in the comment field of each estimated dipole as medical opinion.
The dialog to select dipoles will appear upon executing this command. The dipoles to which
the user attach the comments can be selected by clicking the item in the list of MSI. The user
can also extract the dipoles from the list in accordance with a certain condition. After clicking
the OK button, the comment field will be appear. The user can make a comment for the
selected dipoles within 80 characters.
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5.8 Delete MSI Entry
The commands in this category delete the entries of magnetic source from the MSI list.
5.8.1 Delete current Entry
All the magnetic entries at the selected time slice will be deleted.
5.8.2 Delete series Entries
All the magnetic entries in the selected series of the time slices will be deleted.
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5.8.3 Delete specified Entries
The MSI list will appear upon selecting the command. The user can select the specific
magnetic source to be deleted from the list.
5.8.4 Delete multiple Entries
If there are multiple MSI entries on the selected time slice, this command can delete the
entries at once.
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5.8.5 Delete all Entries
All magnetic source entries will be deleted.
5.9 Book Mark
The user can put a mark called “book mark” on any time slice by this command. There are
two types of book mark. One is retained type which is preserved with the data in the file upon
saving. The other is temporal type which is not saved in the file and vanishes upon closing
the file. The user can label and make a comment for each book mark.
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5.10 Entry Book Mark from MSI
The user can set a book mark to the time slice at which a dipole is estimated. The dialog to
select dipoles will appear upon executing this command. The dipoles to which the user set the
book mark can be selected by clicking the item in the list of dipoles. The user can also extract
the dipoles from the list in accordance with a certain condition. After clicking the OK button,
the dialog selecting the type of book mark between retained and temporal will be appear.
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5.11 Delete Book Mark Entry
5.11.1 Delete current Entry
The book mark at the selected time slice will be deleted.
5.11.2 Delete series Entries
The book marks in the selected series of the time slices will be deleted.
5.11.3 Delete specified Entries
The list of the book marks will appear upon selecting the command. The user can select the
specific book marks to be deleted from the list.
5.11.4 Delete all Entries
All book marks will be deleted.
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6. Tool
6.1 Statistics of Data
Minimum, maximum, average, range, and standard deviation of the data for each channel can
be displayed in the dialog. The channels that have the maximum range, the minimum range,
the maximum standard deviation, and the minimum standard deviation are shown with their
values. The grand average and the grand standard deviation is calculated through all the
selected channels. The time region for the calculation can be selected.
The resulting data is displayed with 16 channels per “page.” The information in the dialog can
be exported to a text file from the File menu.
The start time and the end time over which to
calculate the statistics must be specified.
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6.2 Statistics of MSI
The spatial distribution of the location of the magnetic source in the MSI list will be shown in
the dialog. The information in the dialog can be exported to a text file from the File menu.
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6.3 Auto Correlation
There are several correlation options built in to Meg Laboratory. A (bivariate) correlation is
a statistical analysis that examines the relationship between two variables; if there is a strong
predictive relationship between two variables – either positive (e.g., if one rises, the other
rises, like difficulty of a sentence and processing time), or negative (e.g., if one rises and the
other falls, like loudness of a stimulus and time to perception) – then there will be a strong
correlation between the variables.
The correlation functions in Meg Laboratory permit the examination of a sensor’s
relationship to itself over a variety of time ranges (“autocorrelation”), to another sensor over a
variety of time ranges (“cross correlation”), to another sensor at only one time range
(“correlation”), to all sensors at only one time range (“correlation map”), and to the analogous
sensor from another file/condition at one time range (“file correlation”).
Autocorrelation of data of a selected channel will be calculated upon selecting this command.
“Autocorrelation” is the correlation of one sensor to itself. The result will be shown in the
dialog.
1) Enter the start time and end
time of the range over which to
perform the correlation.
2) Make sure the appropriate channel is specified.
3) Press “Display.”
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6.4 Cross Correlation
Cross-correlation of data of two selected channels will be calculated and the result will be
shown in the dialog. The relationship between two different sensors is examined over varying
time intervals to see if a predictive relationship exists between an earlier time and a later time.
6.5 Correlation
The user must select two channels in the waveform viewer before executing this command.
The command calculates the correlation coefficient of the two channels and shows the result
in the dialog.
1) Enter the start time and end time of
the range over which to perform the
correlation.
2) Make sure the appropriate
channels are specified.
3) Press “Display.”
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6.6 Correlation Map
The user must select one channel in the waveform viewer before executing this command.
The command calculates a cross-correlation coefficient between the selected channel and the
other channels. It means that a cross-correlation coefficient with the selected channel is
assigned to each channel. The set of cross-correlation coefficients is exported to a new MEG
data file which has just one time slice. The contour map of the cross-correlation coefficients
can be shown in the created MEG data file.
6.7 File Correlation
A dialog to select a MEG data file will appear. The Cross-correlation coefficient between the
data of the active file and the selected file is calculated. The two files must have the same data
attributes (sensor configuration, sampling rate, data length, etc.).
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6.8 t-test
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6.9 Time-Integral
All the data of each channels are integrated along the temporal axis. The result is shown in the
manner of the contour map. The time region for integration can be selected. The way to
integrate can be selected from Summation of Signed, Summation of Absolute, and Root of
Square-Summation.
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6.10 FFT Amplitude
The Amplitude Spectrum dialog will open. Select the channels to be calculated. The user
can then select Start Time, Number of points, Window Type, and Scale for the calculation.
Amplitude Spectrum is calculated by FFT and the result can be shown graphically in the
dialog upon clicking the Display button. It can be exported to a text file. Averaging along the
temporal axis can be applied by the command in the Option menu.
1) Select the appropriate channels (up to 32); these should
be entered separated by a comma; or , by pressing the Select
Channel button, the channel map is opened (see 8.19).
2) Enter the starting time (since the FFT
is calculated over a period of time, and
not at a single point, this requires some
forethought).
3) Choose the number of points to be used, using the pull-down
menu. This is similar to choosing the end time; the more points
are chosen, the more accurate the result – however, some
averaged files, particularly those with lower sampling rates,
will not be able to support many of the options. The users can
see that the amount of time included does depend on the
sampling rate and the data length.
4) Press “Display.”
Frequency bands are listed along the bottom.
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6.11 FFT Power
The Power Spectrum dialog will open. Select the channels to be calculated. The user can
then select Start Time, Number of points, Window Type, and Scale for the calculation. Power
Spectrum is calculated by FFT and the result can be shown graphically in the dialog upon
clicking the Display button. It can be exported to a text file. Averaging along the temporal
axis can be applied by the command in the Option menu.
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6.12 FFT Phase
The Phase Spectrum dialog will open. Select the channels to be calculated. The user can
select Start Time, Number of points, Window Type, and Scale for the calculation. Phase
Spectrum is calculated by FFT and the result can be shown graphically in the dialog upon
clicking the Display button. It can be exported to a text file. Averaging along the temporal
axis can be applied by the command in the Option menu.
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6.13 FFT Map
The amplitude and phase components calculated for every sensor by FFT at the specific
frequency or the amplitude components in the specific band are shown in the manner of the
contour map upon clicking the Display button.
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6.14 Time-FFT Map
The temporal transition of the FFT Map is calculated and the result is exported to another file
in the MEG data file format.
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7. Property
The commands in this category show the attributes of the MEG data file. Every command
produces another dialog that displays the information. The information of the dialog is then
exported to a text file.
7.1 Basic Info
The information about the MEG system by which the MEG data file was recorded will be
shown. It contains system name, model name, system ID, version of the software, the number
of the channels, the time when the file was created.
7.2 Patient Info
The information about the patient, patient ID, patient’s name, birthday, sex, and dominant
hand, will be shown.
7.3 History Info
The history of the user’s operations for the data file will be shown.
7.4 Channel Info
The sensor type, the locations and directions of each sensor in the MEG coordination system
will be shown.
7.5 Calibration Info
The sensor type, sensitivity, and offset of each sensor will be shown.
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7.6 FLL Info
The parameters of SQUID sensor, bias current and offset voltage, will be shown for each
sensor.
7.7 Amp and Filter Info
The gain of amplifiers and the cut-off frequency of the filters will be shown.
7.8 Acquis Condition Info
For the data file recorded in continuous raw data acquisition mode, sampling rate, acquisition
time, actual time, and trigger mode will be shown. For the data file recorded in evoked
average data acquisition mode, sampling rate, frame length, pre-trigger length, post-trigger
length, condition of level rejection, averaged count, actual averaged count, rejected count, and
trigger conditions will be shown.
7.9 Trigger Event Info
The information about the trigger event will be shown.
7.10 MRI Info
The filename of the MRI data file linked to the MEG data file, the information of conductor
model fit to the MRI data, head coordination system information will be shown. The
conductor model information is displayed in the MRI coordination system.
7.11 MRI-MEG Matching Info
The information about the location of markers and transformation between MRI coordination
system and MEG coordination system will be shown. The filename of the linked MEG maker
file, the position of MEG and MRI makers described in MRI coordination system, transform
matrix between the two coordination system, the distance between two of the five markers,
and the deviation between the position of MRI markers and the transformed position of MEG
markers are included.
7.12 Measured Data Info
The data at the selected time slice will be shown in Tesla, A/D, or Volt units.
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7.13 Magnetic Source Info
The information of the estimated theoretical magnetic sources will be shown. The location,
direction and intensity of the current dipoles, and the date and time of when the magnetic
source was recorded is included.
7.14 Book Mark
The information of the book marks will be shown.
7.15 Save Any Properties As
All information displayed by the commands in this category is exported to a text file. The
user can select the information to be exported on the dialog that appears upon executing this
command.
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8. View
An MEG data file contains many kinds of information - not only the data from the sensor.
The commands in this category are used for selecting the information displayed on the screen
and changing the arrangement in the data window.
8.1 Toolbar
This command toggles the toolbar on and off.
8.2 Status Bar
This command toggles the status bar on and off.
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8.3 Layout
The main window to display the MEG data file has five zones. They are: title, waveform
viewer, isofield contour map, MRI viewer, and magnetic source report. The commands in this
category switch the arrangement of the five zones in the window.
8.3.1 Standard Layout
The title, waveform viewer, isofield contour map, MRI viewer, and magnetic source report
are arranged as the following figure:
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8.3.2 Waveform Leftside
The title, waveform viewer, isofield contour map, MRI viewer, and magnetic source report
are arranged as the following figure:
8.3.3 Waveform Upside
The title, waveform viewer, isofield contour map, MRI viewer, and magnetic source report
are arranged as the following figure:
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8.4 Standard 3-View
Title, waveform viewer, isofield contour map, and MRI viewer are shown. This set is called
the standard 3-view arrangement.
8.5 Standard 4-View
Title, waveform viewer, isofield contour map, MRI viewer, and magnetic source report are
shown. This set is called the standard 4-view arrangement.
8.6 Title View
The items for the title zone are the patient information, the filename of the MEG data file,
and the condition of the acquisition. The commands in this category switch the information to
be displayed in the title zone.
8.6.1 Show
The display of the title zone can be switched on and off by this command.
8.6.2 Patient Info
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The display of patient information in the title zone, patient name and patient ID, can be
switched on and off by this command.
8.6.3 File Extension
The display of the file extension in the filename in the title zone can be switched on and off
by this command.
8.6.4 Acquis Condition
The display of the condition of the acquisition, which contains the measurement date and
time, the setting of the filters, the sampling rate, and average count, can be switched on and
off by this command.
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8.7 Waveform View
8.7.1 Full Size
Only the waveform viewer and the title zone are shown on screen upon executing this
command.
8.7.2 Show
The display of the waveform viewer can be switched on and off by this command.
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8.7.3 Display Range
Display Range dialog will appear upon executing the command. The time slice to be operated
can be selected numerically. The user can display the range, both in x-axis and y-axis, in the
waveform viewer. If the user input too narrow range to display, the values are modified
automatically.
8.7.4 EEG scale
The scales of x and y axis of waveform viewer are changed to the appropriate expression for
the EEG signals by this command.
8.7.5 Overlap
The data of every selected channel is displayed in overlap mode. The graph in this mode is
sometimes called a ‘butterfly plot.’
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8.7.6 Parallel
The data of every selected channel is displayed in parallel.
8.7.7 Gridmap
The data of every channel is displayed in gridmap mode.
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8.7.8 Tesla
The command changes the unit of y-axis to Tesla. The unit is transformed from A/D to Tesla
using the information for the gain of amplifiers and the sensitivity of each SQUID sensor.
8.7.9 A/D
The command changes the unit of y-axis to A/D. A/D is the original unit of the data acquired
by data acquisition system. This unit is converted to Tesla based on the information from the
gain of amplifiers and the sensitivity of each SQUID sensor.
8.7.10 Voltage
The command changes the unit of y-axis to Volts.
8.7.11 RMS only
The Route Mean Square of all signals for the selected channels is calculated at every time
slice. The RMS waveform is only displayed on the waveform viewer. This command is
effective only when the waveforms are displayed in overlap mode.
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8.7.12 RMS also
The Route Mean Square for all the signals of the selected channels is calculated at every time
slice. The RMS waveform and the selected signals are displayed together on the waveform
viewer. This command is effective only when the waveforms are displayed in overlap mode.
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8.7.13 Splitter Waveform
The waveform viewer can be separated into two parts to show the data for the two different
sets of channels. For example, if the users wanted to view left- and right- hemisphere
activations simultaneously but not superimposed, the users could use this command. The
commands in this category affect the second set in the waveform viewer.
8.7.13.1 Full Size
The command makes the second set of the data occupy the waveform viewer.
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8.7.13.2 Show
The display for the second data set in the waveform viewer can be switched on
and off by this command.
8.7.13.3 Overlap
The data for every selected channel in the second data set is displayed in overlap
mode. The graph in this mode is sometimes called a ‘butterfly plot.’
8.7.13.4 Parallel
The data for every selected channel in the second data set is displayed parallel.
8.7.13.5 Tesla
The command changes the unit of y-axis to Tesla for the second data set display.
The unit is transformed from A/D to Tesla using the information of the gain of
amplifiers and the sensitivity of each SQUID sensor.
8.7.13.6 A/D
The command changes the unit of y-axis to A/D for the second data set display.
A/D is the original unit of the data acquired by data acquisition system. This unit
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is converted to Tesla based on the information of the gain of amplifiers and the
sensitivity of each SQUID sensor.
8.7.13.7 Voltage
The command changes the unit of y-axis to Volts for the second data set display.
8.7.13.8 Select Channel
Upon executing this command, Select Channel dialog will appear to select the
channels for the second data set display. (See 8.19)
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8.7.14 Background
The display of the axes, grid lines, and labels in the waveform viewer (in overlap and parallel
modes), can be switched on and off by this command.
In the case of gridmap mode, the display for the channel number, scales, outline of the head,
and the indication of left and right, can be switched on and off by this command.
8.7.15 Outline
The display for the outline of the patient’s head in the waveform viewer (in gridmap mode)
can be switched on and off by this command. This command is effective only when the
waveforms are displayed in gridmap mode.
8.7.16 Epoch Frame
The time frames of each epoch to be extracted for averaging are displayed on waveform
viewer by this command.
8.7.17 X-Cursor
The cursor for x-axis can be switched on and off with this command.
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8.7.18 Y-Cursor
8.7.18.1 Show
The cursor for y-axis can be switched on and off with this command. This
command is only effective when the waveforms are displayed in overlap mode.
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8.7.18.2 Mouse Cursor
The display of the value at the position indicated by clicking on the waveform
viewer can be switched on and off by this command. This command is effective
only when the waveforms are displayed in overlap mode.
8.7.18.3 Maximum
The display of the maximum value of the selected data at the time slice indicated
by the x-cursor can be switched on and off with this command. This command is
only effective when the waveforms are displayed in overlap mode.
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8.7.18.4 Minimum
The display of the minimum value for the selected data at the time slice
(indicated by the x-cursor) can be switched on and off with this command. This
command is only effective when the waveforms are displayed in overlap mode.
8.7.18.5 RMS
The display of the RMS value for the selected data at the time slice (indicated by
the x-cursor) can be switched on and off with this command. This command is
only effective when the waveforms are displayed in overlap mode.
8.7.19 Book Mark
This command switches on/off the display of the bookmarks on waveform viewer.
8.7.20 Non-MEG Channels on Gridmap
The display of Non-MEG channels on the waveform viewer, in gridmap mode, can be
switched on and off with this command. This command is only effective when the waveforms
are displayed in gridmap mode.
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8.7.21 Reference Waveform
The user can view data from two or more MEG data files simultaneously in the same window.
This command brings up the dialog to choose two or more MEG data files. This command
will NOT work if files are of different lengths, and if a file is not baseline-adjusted. Files
viewed with this command should already be processed (e.g., baseline-adjusted).
• To view files either overlapping or
parallel, use the Add button.
• To remove files from view, use the Delete
button.
• To insert a reference waveform within the
list already created, use the Insert button.
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8.8 Contour Map View
8.8.1 Full Size
Only the isofield contour map and the title zone are shown on the screen upon executing this
command.
8.8.2 Show
The display of the isofield contour map can be switched on and off with this command.
8.8.3 Measured Contour
An isofield contour map based on the observed magnetic fields at the selected time slice is
shown singularly.
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8.8.4 Measured + Theoretical Contour
The Two isofield contour maps, based on the observed magnetic fields and the theoretical
magnetic fields calculated from the estimated current dipoles at the selected time slice, are
shown. If there is no entry of MSI at the selected time slice, the theoretical map isn’t shown.
8.8.5 Measured + Theoretical + Residual Contour
The Three isofield contour maps, based on the observed magnetic fields, the theoretical
magnetic fields calculated from the estimated current dipoles, and the residual magnetic
fields in the estimation, are shown. If there is no entry of MSI at the selected time slice, the
theoretical and residual maps aren’t shown.
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8.8.6 Auto
The software chooses one of the three modes automatically which are: Measured, Measured
+ Theoretical, and Measured + Theoretical + Residual. These are based on the area for the
isofield contour map. If there is sufficient space to display the three contour maps, and the
theoretical current dipoles are estimated for the selected time slice, the software will choose
the Measured + Theoretical + Residual mode.
8.8.7 2-Color Contour
The contour map is only described by lines. Two colors are used on the contour map to
express the rising fields from the patient’s head and the sinking fields into the head.
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8.8.8 Line Contour
The contour map is only described by lines. Two colors are used in the contour map to
express the rising fields from the patient’s head and the sinking fields into the head. The
brightness of the color of the lines is changed by the intensity of the field assigned to the lines.
The less intensity is represented by the darker lines.
8.8.9 Gradation Contour
The contour map is filled by two tone colors. The higher intensity area is filled by the
stronger color.
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8.8.10 Line Gradation Contour
The contour map is filled by two tone colors. The higher intensity area is filled by the
stronger color. The border lines between the two adjacent areas are also displayed.
8.8.11 Auto Gain
If this option is selected (checked), the step value between lines are adjusted automatically to
fit the amplitude of the wave. If this option is deselected, the scale of the contour map will
remain constant, unless it is adjusted manually.
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8.8.12 Whole Area
When this option is checked, the contour map for the whole area is displayed without
reference to the selected channels. If this option is not checked, the contour map only for the
adjacent area of the selected channels is displayed.
8.8.13 Background
The display of the title, the scale, and the indication of left and right can be switched on and
off with this command.
8.8.14 Outline
The display of the outline of the patient’s head in the contour map can be switched on and off
with this command.
8.8.15 Channel Position
The display of the grid representing the position of each SQUID sensor can be switched on
and off with this command.
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8.8.16 Channel Number
The display of the channel number beside the corresponding grid on the contour map can be
switched on and off with this command. This command is only effective when the channel
positions are displayed.
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8.9 MRI View
The MRI viewer can display not only the MR image but also the assigned sphere model, the
arrangement of the sensor array, the estimated theoretical current dipoles, etc. The command
in this category treats the spatial information to be displayed in the MRI viewer in the manner
of the projection from the three orthogonal directions.
8.9.1 Full Size
Only MRI viewer and title zone are shown on screen upon executing this command.
8.9.2 Show
The display of the MRI viewer can be switched on and off with this command.
8.9.3 Axial View
The display of the axial view in the MRI viewer can be switched on and off with this
command.
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8.9.4 Coronal View
The display of the coronal view in the MRI viewer can be switched on and off with this
command.
8.9.5 Sagittal View
The display of the sagital view in the MRI viewer can be switched on and off with this
command.
8.9.6 Background
The display of the title, the slice number, and the indication of left / right and anterior /
posterior can be switched on and off with this command.
8.9.7 MR-Image
The display of the MRI data linked to the active MEG data file can be switched on and off
with this command.
8.9.8 MEG Sensor
The display of the arrangement of the sensor array can be switched on and off with this
command.
8.9.9 MEG Marker
The display of the positions for the MEG markers in the MRI viewer can be switched on and
off with this command.
8.9.10 MRI Marker
The display of the positions for the MRI markers in the MRI viewer can be switched on and
off with this command.
8.9.11 Sphere Model
The display of the sphere conductor model assigned to the MRI data can be switched on and
off with this command.
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8.9.12 Contour Map
The display of the three dimensional contour map in the MRI viewer can be switched on and
off with this command.
8.9.13 Dipole
The display of the location and direction of the estimated theoretical current dipoles in the
MRI viewer can be switched on and off with this command.
8.9.14 Coordinate Frame
The display of the frame for the MRI coordination system can be switched on and off with
this command.
8.9.15 Slice Position
The display of the indication for the selected MRI slice can be switched on and off with this
command.
8.9.16 Display All
When this command is executed, all of the options described above will be displayed in the
MRI viewer.
8.9.17 Link to Dipole #1
When this option is enabled, the slice including the location of the estimated theoretical
dipole #1 is displayed in the MRI viewer, upon selecting the time slice at which there is an
MSI entry.
8.9.18 Link to Dipole #2
When this option is enabled, the slice including the location of the estimated theoretical
dipole #2 is displayed in the MRI viewer, upon selecting the time slice at which there are two
or more MSI entries.
8.9.19 No Link to Dipole
When this option is enabled, the displayed slice isn’t changed even upon selecting a time
slice at which there is an MSI entry.
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8.9.20 Reference Dipoles
The positions of the estimated dipoles in the other time slices can be displayed in the MRI
viewer with this command. The dialog for selecting the dipoles to be displayed from the MSI
list will appear upon executing the command.
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8.9.21 Reference Dipoles of Other File
The positions of the estimated dipoles in other MEG data files can be displayed in the MRI
viewer with this command. This dialog sets the dipoles to be displayed. Another dialog to
select the other MEG data file will appear upon clicking the Add button. After selection of
the MEG data file, the MSI list of the selected file will appear.
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8.10 MSI Report View
MSI Report viewer is the numerical display of the theoretical current dipoles estimated for
the selected time slice. The commands in this category change the characteristics of MSI
Report viewer.
8.10.1 Full Size
Only MSI Report viewer and title zone are shown on screen upon executing this command.
8.10.2 Show
The display of MSI Report viewer can be switched on and off with this command.
8.10.3 MEG Coordinate
The coordination system for the values of the positions and directions in the MSI Report
viewer is changed to the MEG coordination system upon executing the command.
8.10.4 MRI Coordinate
The coordination system for the values of the positions and directions in the MSI Report
viewer is changed to the MRI coordination system upon executing the command.
8.10.5 Head Coordinate
The coordination system for the values of the positions and directions in the MSI Report
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viewer is changed to the head coordination system upon executing the command. The
command is selectable only when the head coordination system is defined.
8.11 MSI Select View
The user can mark the dipoles adapting to specific conditions regarding latency, GOF of
estimation, intensity of the dipole, date and time for the estimation, comment text, and labels.
The dialog to set the condition will appear upon executing the command.
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8.12 Select View Format
8.12.1 Show
The display of the marks for the selected dipoles by “MSI Select View” in section 8.11 on
both of Waveform View and MRI View can be switched on and off by this command.
8.12.2 Waveform View
The display of the marks for the selected dipoles by “MSI Select View” in section 8.11 on
Waveform View can be switched on and off by this command.
8.12.3 MRI View
The display of the marks for the selected dipoles by “MSI Select View” in section 8.11 on
MRI View can be switched on and off by this command.
8.12.4 Colored by Label
The colors of the marks are determined by the label for each MSI entry by choosing this
command.
8.12.5 Colored by Time
The colors of the marks are determined by the time slice for each MSI entry by choosing this
command.
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8.12.6 Colored by GOF
The colors of the markers are determined by the GOF of each MSI entry by choosing this
command.
8.12.7 Colored by Intensity
The colors of the markers are determined by the intensity of each MSI entry by choosing this
command.
8.12.8 Colored by Time order
The color gradation in accordance with the latency of each MSI entry is applied to the
markers by choosing this command.
8.12.9 Colored by GOF order
The color gradation in accordance with the GOF of each MSI entry is applied to the markers
by choosing this command.
8.12.10 Colored by Intensity order
The color gradation in accordance with the intensity of each MSI entry is applied to the
markers by choosing this command.
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8.13 Search Next
This command can scan the dipole fulfilling the given condition along the lines of temporal
axis. The dialog to set the conditions will be appeared upon selecting the command. When
the OK button is clicked, the nearest dipole from the current time slice is indicated in
Waveform View.
8.14 Select View All
All conditions to select specific dipoles are canceled and all dipoles in the MSI entry is
marked by choosing this command.
8.15 Series View
The user can select two or more time slices in the specific time region by dragging the mouse
on the waveform viewer while pressing SHIFT. The selected time region is filled by the
different color from the other region on the waveform viewer. The software can treat the
selected time slices as a series. The commands in this category are related to the series.
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8.15.1 Show
The display of the series can be switched on and off by executing this command.
8.15.2 Waveform View
Every time slice at which the theoretical current dipoles are estimated in the series is
indicated by the pin-like mark when this option is enabled.
8.15.3 MRI View
The position of every dipole in the series is displayed on the MRI viewer when this option is
enabled.
8.15.4 Contour Map Window
The contour map at every time slice in the series is displayed on another window upon
executing this command.
8.15.5 MR-Image Window
This function has not been implemented yet.
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8.16 Series View of All MSI
The time slices in the time region including all estimated MSI are automatically selected as a
series with this command.
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8.17 Graphic Attribute
The user can customize the appearance and the default settings of the data window by the
commands in this category.
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8.17.1 Frame Attribute
The attributes related to the frame of the viewer can be changed in the dialog opened with
this command.
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8.17.2 Waveform Attribute
The attributes related to the waveform viewer can be changed in the dialog opened with this
command.
8.17.3 Contour Attribute
The attributes related to the contour map can be changed in the dialog opened with this
command.
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8.17.4 MRI Attribute
The attributes related to the MRI viewer can be changed in the dialog opened with this
command.
8.17.5 Serial/Select View Attribute
The attributes related to Serial view and Select view can be changed in the dialog opened
with this command.
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8.17.6 Initial View Attribute
The initial state of each viewer and the options to be enabled upon opening the MEG data file
can be set in the dialog opened with this command.
8.17.7 Init All Attribute
All the settings of the attribute are returned to the initial state with this command.
8.17.8 Import All Attribute
All the settings of the attribute are imported from the attribute file.
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8.18 Associated windows
The commands in the Tool or Property category will make another dialog. These dialogs are
not modal and arrangement of the dialogs is controlled by the commands in this category.
8.18.1 Minimize
The active dialog will be minimized.
8.18.2 Maximize
The active dialog will be maximized
8.18.3 Normalize
The size of the active dialog will be reset to the initial size.
8.18.4 Close
The active dialog will be closed.
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8.18.5 Minimize others
Dialogs other than the active one will be minimized.
8.18.6 Maximize others
Dialogs other than the active one will be maximized.
8.18.7 Normalize others
The size of dialogs other than the active one will be reset to the initial size.
8.18.8 Close others
Dialogs other than the active one will be closed.
8.18.9 Minimize all
All dialogs will be minimized.
8.18.10 Maximize all
All dialogs will be maximized.
8.18.11 Normalize all
The size of all dialogs will be reset to the initial size.
8.18.12 Close all
All dialogs will be closed.
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8.19 Select Channel
The dialog to select the channels to be displayed on the waveform viewer will appear upon
executing this command. This dialog is used for selection of the sensors when the Select
Channel button on the other dialog is clicked.
8.20 MSI Using Channel
With this command, the channels whose data are used for the estimation of the theoretical
current dipoles at the time slice are selected to be displayed on the waveform viewer.
Click on channels
above or below.
Dragging is also
effective.
Choose from:
•Set mode: simply click
on or draw a box around
selected sensors. Shiftclick
adds sensors, Ctrlclick
removes them.
•Add mode: where every
sensor clicked on is added.
•Delete mode: where
every sensor clicked on is
deleted.
•Toggle mode: where a
click toggles the setting of
selected sensors.
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9. Window
9.1 New Window
This command opens another window of the same data file as the active file.
9.2 Cascade
This command arranges the windows in cascade.
9.3 Tile Horizontal
The windows on the screen are tiled horizontally.
9.4 Tile Vertical
The windows on screen are tiled vertically.
9.5 Arrange Icons
The minimized windows are arranged in order.
10. Help
10.1 About MegLaboratory...
Copyright and the version information is displayed on another dialog with this comma