Brainsight

This module provides import and export functions for the Brainsight TMS Navigator software.

Several coordinate systems are supported for export and import of coil data. SimNIBS always uses the RAS coordinate system (NIfTI). This and the LPS coordinate system used for DICOMS is supported here.

The Brainsight ecosystem provides two main ways of storing positions/orientations: Targets and Samples. Both are exported in a single .txt file.

How to use

Export from Brainsight

Choose NIfTI:aligned (preferred) or World coordinate systems while exporting the coil data.

Import to SimNIBS

simnibs.brainsight.read(fn) reads exported coil information from Brainsight and returns two simnibs.TMSLIST() objects: One for Targets and one for Samples. The conversions from LPS (called World in Brainsight) to RAS for SimNIBS and the different coil axes definitions are performed automatically.

Import a single Brainsight .txt file as simnibs.TMSLIST()

from simnibs import sim_struct, brainsight

s = sim_struct.SESSION()

fn = "exported_data.txt"
tms_list_targets, tms_list_samples = brainsight().read(fn)  # read all Targets and Samples from file and return as TMSLIST() each
s.add_tmslist(tms_list_targets)

tms_list.pos[0].name  # <- name is filled with data from .txt.

Export from SimNIBS

simnibs.brainsight.write(obj, fn) writes an .xml file that is compatible for Brainsight import. The conversion between the different coil axes definitions is performed automatically. When World, i.e. LPS coordinate system is selected for export the conversion is performed automatically.

Export a file for precomputed positions/orientations

from simnibs import sim_struct, opt_struct, brainsight
fn = "precomuted_coilpos.xml"

### export from TMSLIST
tmslist = sim_struct.TMSLIST()
tmslist.add_position()
# ... define (multiple) positions ...
brainsight().write(tmlist, fn, out_coord_space='LPS')

### export from POSITION
pos = sim_struct.POSITOIN()
pos.matsimnibs = ...
brainsight().write(pos, fn) # out_coord_space default is 'RAS'

### export from np.ndarray / matsimnibs
opt = opt_struct.TMSoptimize()
# ... prepare optmization ...
opt_mat = opt.run() # get optimal position
brainsight().write(opt_mat, fn)

Notes

• The same anatomical scan has to be used for TMS Navigator and SimNIBS.

• The same coil model has to be used for field simulations and for real stimulation.

• Coordinate systems used to define coil axes for SimNIBS and Brainsight: