Summary of key anatomic tracts and structures

Structure	Figure	Regions Connected	Relevant Disorders	Hypothesized Effects of Stimulation
AL	Fig 4B, -D (yellow)	GPi, VOa	PD and dystonia	Improve dystonia and dyskinesia
AS	Fig 4B, -C (purple); Fig 3B, -C (blue)	STN, GPi	PD and dystonia	Direct stimulation effect unknown
ATR	Fig 5A, -B (red)	Thalamus, prefrontal cortex	OCD	Improve OCD
DRTT	Fig 1C, -D (red and green); Fig 4D (green)	DN, RN, VIM/VOp, M1	ET and tremor-predominant PD	Improve tremor, worsen ataxia
FL	Fig 2A; Fig 4D (red)	GPi, VOa	PD and dystonia	Improve dystonia and parkinsonism
FS	Fig 3B, -C (Pink); Fig 4B, -C (red)	STN, GPe	PD and dystonia	Direct stimulation effect unknown
Hyperdirect pathway (limbic/associative)	Fig 3A (cyan, yellow)	STN, broad limbic and associative regions	OCD	Improve OCD
Hyperdirect pathway (motor)	Fig 3A (orange)	STN, motor cortex	PD	Improve parkinsonism
MMT	Fig 6C (green)	Mammillary body, ANT	Epilepsy	Decrease seizures
MFB	Fig 5A, -B (cyan)	VTA, nucleus accumbens and olfactory cortex	Depression (off-label use)	Possibly worsens OCD
TF	Fig 2A	Combination of FL, AL, and DRTT, thalamus	PD, dystonia, ET	Improve tremor
vtaPP (formerly slMFB)^{^a}	Fig 5A, -B (green)	DN, VTA, SFG, MFG, and lateral OFC	OCD	Possibly improve OCD
ANT	Fig 6A–C		Epilepsy	Decrease seizures
VIM	Fig 1A–C; Fig 4D		ET and tremor-predominant PD	Improve tremor, worsen ataxia, dysarthria
VOa/VOp	Fig 1A, -B; Fig 4D		ET and tremor-predominant PD	Improve tremor, dystonia, worsen ataxia
ZI	Fig 1C; Fig 2A		ET and tremor-predominant PD	Improve tremor, worsen ataxia

Note:—DN indicates dentate nucleus; M1, primary motor cortex; MFG, middle frontal gyrus; OFC, orbitofrontal cortex; RN, red nucleus; SFG, superior frontal gyrus; VOa, ventralis oralis anterior; VOp, ventralis oralis posterior; VTA, ventral tegmental area; vtaPP, projection pathway from the ventral tegmental area.
↵a vtaPP (slMFB) likely represents misidentification of the limbic/associative hyperdirect pathway.