BESA files extensions

Module information
Modules	BESA Research Basic or higher
Version	5.2 or higher

One of the most important rules in BESA software is that the original data will never be changed during data processing (unless user explicitly want to do it by himself). All the changes (i.e. signal processing like filtering) performed in BESA are kept in PC memory and not saved to the file. Such approach has a drawback, that all the settings have to be regenerated whenever the data file is reopened. Therefore to keep all the settings and reload them whenever file is opened BESA saves the additional files beside original one (with the same name, but with different file extension). Note that Such approach has one additional advantage: whenever user want to start his analysis from a scratch he or she just need to delete file responsible for particular setting (or all files to get completely initial state). Therefore good understating of BESA file nomenclature might be useful for advanced BESA users.

Besa Research file extensions

Application	File extension	File function	When generated/changed
Main	.atf	artifact coefficients	After setting up artifact correction (right mouse click, "Define artifact topography" menu)
Main	.bad	bad channels	Whenever any of the electrode is marked as bad or is interpolated
Main	.cot	Head center coordinate	external file loaded to BESA. Information about file localization saved in .fst file
Main	.ela, .elp, .eps	additional electrode configuration files	When electrodes configuration was loaded (File menu, Load Channel Configuration). *.elp file can be manually saved in "File → Head Surface Points and Sensors → Save Electrode File for Current Montatage"
Main	.evt	Events	external text file. Can be loaded by selecting "ERP → open event file…" (and saved by "ERP → save event file…"). After loading information is copied to .ftg and .fst file is updated
Main	.fst	File general setup	File opened for first time, updated whenever various settings changed (i.e. filtration parameters, surface point file localization)
Main	.ftg	Triggers	On file close
Main	.ica	ICA topography	Can be saved after ICA analysis by clicking with right mouse button on selected component and selecting "Save Topography"
Main	.mtg	Montages	If montage was changed, just .fst file updated. Mtg files are kept in "C:\Users\Public\Documents\BESA\Research_6_1\Montages"
Main	.pdg	paradigm	after loading or creating the paradigm
Main	.pmg	MEG sensor coordinates	external file loaded to BESA. Information about file localization saved in .fst file
Main	.pos	MEG sensor coordinates	external file loaded to BESA. Information about file localization saved in .fst file
Main	.sfh	coregistration info	created when coregistration with MRI is started ("File → MRI Coregistration.."). Can be loaded externally, then information about file localization is saved in .fst file
Main	.sfn	labels assigned to electrode configuration .eps	external file loaded to BESA. Information about file localization saved in .fst file
Main	.sfp	digitalized head surface points coordinates	external file loaded to BESA. Information about file localization saved in .fst file
Export	.avr	ASCII vectorized data file	Can be generated by "File → Export…"
Export	.dat	simple binary matrix with data	Can be generated by "File → Export…"
Export	.edf	EDF+ (European data format) data file	Can be generated by "File → Export…"
Export	.foc	BESA continuous native data file	Can be generated by "File → Export…"
Export	.fsg	BESA averaged native data file	Can be generated by "File → Export…"
Export	.generic	Additional header file for binary data (.dat)	file automatically created when binary data file was exported.
Export	.mul	ASCII multiplexed data file	Can be generated by File->Export…
Export	0.001, 0.002 …	ASCII vectorized or multiplexed epochs around triggers	Can be generated by File->Export… File extension indicates epoch number
Top Viewer	.bmp	bitmap file	Save of current state of Top Viewer (File menu, Save as Bitmap...)
Top Viewer	.eps	EPS graphic file	Save of current state of Top Viewer (File menu, Save as eps file...)
Top Viewer	.tva	Top viewer arrangement	On Top Viewer close, if settings or electrode position was changed
Top Viewer	.tvs	Top Viewer settings	On Top Viewer close, if settings or electrode position was changed
Time Frequency Analysis	.tfc	Averaged time-frequency data	Can be created when Time-Frequency Analysis is used ("ERP → coherence tab")
Time Frequency Analysis	.tfcs	Single trial time-frequency data	Can be created when Time-Frequency Analysis is used ("ERP → coherence tab")
Source Analysis	.bmp	bitmap file	Save of current state of 3D window ("File → Save 3D window as a bitmap...")
Source Analysis	.bsa	Source analysis solution (i.e. dipoles)	can be loaded or saved in menu of source analysis window ("File → Save Solution..")
Source Analysis	.dat	3D Image ASCII file or voxel values for each dipole orientation	Can be exported in 3D window of Source Analysis ("Image → Export Image as…") if sources for more than one latency was computed you can select option to save voxel values for each dipole orientation
Source Analysis	.hdr	3D Image ANALYZE file	Can be exported in 3D window of Source Analysis ("Image → Export Image as…") if sources for more than one latency was computed you can also choose option for all latencies
Source Analysis	.laura	result file of LAURA	After compiling computation of LAURA in Source Analysis
Source Analysis	.loreta	result file of LORETA	After compiling computation of LORETA in Source Analysis
Source Analysis	.swf	Source waveforms	can be saved in file menu of source analysis window ("File → Save Source Waveforms...")
Source Analysis	.vmp	3D Image BrainVoyager File (can be written with current resolution or with 1 mm)	Can be exported in 3D window of Source Analysis ("Image → Export Image as…")
Source Analysis	.vtc	BrainVoyager VTC File for all latencies	Can be exported in 3D window of Source Analysis ("Image → Export Image as…") if sources for more than one latency was computed
Source Analysis	.vts	Image ASCII voxel time series	Can be exported in 3D window of Source Analysis ("Image → Export Image as…") if sources for more than one latency was computed
FFT	.faa, .fap, .far, .fai	Exported amplitude (fma), power (fmp), real (fmr) and imaginary part(fmi) of spectrum for average reference (Interpolated-81) montage	One of export options in FFT window "File → Export FFT data menu" with "Interpolated-81" menu item selected (in the same menu)
FFT	.fba	Exported Amplitude in Bands	In FFT window menu "File → Export Amplitude in Bands"
FFT	.fbp	Exported Power in Bands	In FFT window menu "File → Export Power in Bands"
FFT	.fft	result of FFT	In FFT window "File → save…"
FFT	.fma, .fmp, .fmr, .fmi	Exported amplitude (fma), power (fmp), real (fmr) and imaginary part(fmi) of spectrum for current montage	One of export options in FFT window "File → Export FFT data" menu with "Current montage" menu item selected (in the same menu)