TABLE 1.

Outline of key terms for TMS personalization

	Term	Description	Research question	Answer
Metrics	SGC FC reproducibility	Correlation of FC values across all voxels within the DLPFC for each individual across resting‐state fMRI sessions 1 and 2. For personalization to be viable, SGC FC needs to be consistent across sessions on different days.	Are SGC connectivity maps reproducible across sessions?	Highly reproducible (R = 0.94) given sufficient data quantity (acquisition time ~15–25 min, multiband sequence), quality and methodology.
	Intraindividual distance	Distance between optimal coordinates from data acquired in the same individual on different days. Ideally this distance will be low, indicating high reproducibility.	How reproducible are connectivity‐guided targets within individuals over time?	Targets can be reproduced with a median variation of only 2.2 ± 0.4 mm between scans, subject to the factors noted above and using the cluster‐seedmap method.
	Interindividual distance	Distance between personalized coordinates across different individuals. Higher values indicate better preservation of individual differences or reduced accuracy.	How much variation is there across individuals? Is personalization justified on this basis?	Targets scatter broadly across the spatial extent of the DLPFC. The median interindividual distance was between 16 and 27 mm depending on methodology.
	Ratio of interindividual‐to‐intraindividual distance	Ratio between the variation across individuals to the variation within individuals. Ideally this ratio will be high, reflecting high interindividual distances (i.e., preservation of individual differences), and low intraindividual distances (i.e., high reliability).	Which method best preserves individual differences whilst also providing high intraindividual reproducibility.	This ratio was highest for the combined cluster and seedmap methodology. This ratio improves as acquisition time increases.
	Intrascan FC	The SGC FC value at the optimal DLPFC coordinate within a single neuroimaging session. This value should be negative as methods were designed to identify the site of maximal anticorrelated (i.e., negative) FC with DLPFC. Values should remain negative during the scan session.	Does a selected target maintain its functional fidelity (i.e., negative SGC‐FC) during the scan session?	All methods identified coordinates that remained negative throughout the scan.
	Interscan FC	This metric assesses whether the target from one scan retains its functional fidelity (negative SGC FC) in a scan performed on a separate day.	Will a selected target maintain its functional fidelity (negative SGC FC) over time?	Using appropriate methodology, the target identified in one session displayed negative SGC FC in 100% of individuals in a second scan.
Other key terms	Seedmap method	A method to increase the signal‐to‐noise ratio of subcortical structures such as the SGC.	Are the SGC FC maps derived from seed and seedmap methodologies genuinely comparable and how does the seedmap approach impact the above metrics?	Seedmap derived SGC FC maps faithfully reflected seed‐based maps. The seedmap method improved several measures and did not result in homogenization of target sites.
	Cluster threshold	DLPFC voxels are ranked in order of decreasing values of negative SGC FC. According to the cluster threshold, only the top 0.1 to 50% of most negative voxels are retained, before clustering. Spatial precision decreased as cluster threshold and the resultant cluster size increased (SI results).	What is the optimal cluster threshold?	The optimal threshold depends on data quality and methodology. The optimal threshold was 10% and 0.5% respectively for seed and seedmap based methods.
	Smoothing	Spatial smoothing involves running a small Gaussian kernel across the image to average the intensities of neighboring voxels. Spatial smoothing aims to reduce random noise from individual voxels, while retaining real signal, thereby improving the signal‐to‐noise ratio.	Does heavy smoothing facilitate the identification of optimal personalized target sites, as previously proposed?	No, excessive smoothing introduces a detrimental loss of spatial information and specificity. Minimal smoothing is preferable.