*2.6. nTMS Based DTI-FT of Language Pathway*

The rnTMS cortical mapping was used to obtain the nTMS-based DTI-FT of the principal subcortical pathways of language function: arcuate fascicle (AF), frontal aslant tract (FAT), inferior fronto–occipital fascicle (IFOF), inferior longitudinal fascicle (ILF), superior longitudinal fascicle (SLF), uncinate fascicle (UF) [13,30,31]. The workflow for DTI-FT was performed on the StealthStation S7 navigation system by using StealthViz software (Medtronic Navigation, Coal Creek Circle Louisville, CO, USA). A deterministic approach based on the fiber assignment by continuous tracking (FACT) algorithm was used, with these parameters: FA cut off value = 0.15; vector step length = 0.5 mm; minimum fiber length = 30 mm; seeding density = 1.0; max directional change 90◦ . All language positive spots were imported into the planning station and used to create an overall object with an additional 5-mm border for each cortical spot. Subsequently, the object was exploited like a single ROI for tracking and the StealthViz software created a directionally encoded color map and then a 3D volume of white matter fibers originating from the cortical positive spots previously selected [11]. nTMS-based DTI-FT was able to identify the subcortical network for both languages, consisting of 533 and 293 fibers for Romanian and Italian, respectively. The 3D volumes were then manually elaborated to better visualize the single language-related tracts included in the reconstruction (i.e AF, SLF and ILF) under constant supervision of an expert neuroradiolgist [32–34] (Figure 3). White matter reconstruction displayed an overlap of AF in both languages with the anterior part of the lesion.

**Figure 3.** nTMS-based DTI-FT reconstructions of the language subcortical network in Romanian (**A**) and Italian (**B**) identifies the arcuate fascicle (AF, red), the superior longitudinal fascicle (SLF, yellow) and the inferior longitudinal fascicle (ILF, green) for both languages. In (**C**) the overlap of subcortical tracts is depicted. Italian color code—AF: red; SLF: yellow, ILF: green; Romanian color code—AF: light blue, SLF: blue, ILF violet.
