The authors report the successful management of this debilitating post-midbrain infarction tremor with the insertion of a deep brain stimulator with targets in the contralateral lenticular fasciculus.. 
Although several studies, including our own tracer investigations, suggest that motor projections from GPi principally form the lenticular fasciculus and non-motor projections primarily contribute to the ansa lenticularis, other schemes have perpetuated.
The output fibers of the GPi that form the lenticular fasciculus pass in close proximity to STN DBS electrodes.
Our new finding on magnetic resonance imaging (MRI) of Machado-Joseph disease (MJD) patients indicates degeneration of the lenticular fasciculus (LF), a major outflow of the internal segment of the globus pallidus (GPi).
These axons often follow a long and tortuous course within the GPi and then emerge either through the ansa lenticularis (AL) or the lenticular fasciculus (LF), irrespective of the location of their parent cell body in the GPi.
Therapeutic contacts located in other structures (zona incerta, lenticular fasciculus, or midbrain reticular formation) were also linked to a significant positive effect. In addition, they have confirmed that although the STN is the main target during DBS treatment for PD, stimulation of surrounding regions, particularly the zona incerta or the lenticular fasciculus, can also improve symptoms of PD..
These thin and varicose collaterals emerge from thick and smooth axons that course along the main output pathways of the basal ganglia, including the ansa lenticularis, the lenticular fasciculus and Wilson's pencils.
In opposition to generally accepted schemes, the findings from this study suggest that the pallidothalamic fibers originating from the caudal portions of GPi, including the motor territory, do not course ventromedially to form the ansa lenticularis, but rather, travel predominately medially through the lenticular fasciculus en route to the thalamus.
These thin and varicose collaterals emerge from thick and smooth axons that course backward along the main output pathways of the basal ganglia, including the ansa lenticularis, the lenticular fasciculus and Wilson's pencils.
A possible anatomical basis for these differential functional effects could be a functional somatotopy within the GPi, with the segregation of the pallidofugal fibers from the outer portion of the GPi, on one hand, forming the ventral ansa lenticularis and from the inner portion of the GPi, on the other hand, forming the dorsal lenticular fasciculus..
In contrast, the globus pallidus received a dense dopaminergic innervation deriving mostly from two fascicles that coursed backward along the two major output pathways of the pallidum: the lenticular fasciculus caudodorsally and the ansa lenticularis rostroventrally.
Dopaminergic fibers reached the globus pallidus by coursing along its two major output pathways: the lenticular fasciculus dorsally and the ansa lenticularis ventrally.
Fibers of the lenticular fasciculus appear to terminate preferentially in VLo.
Degenerating pallidothalamic projections emerging from the anterior part of the pallidum formed two diffuse groups of fibers; one coursed ventromedially directly through the internal capsule without forming a lenticular fasciculus and terminated uniformly in the reticular, VA, VD, VM and the medial part of the VE.
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