Globus pallidus interna

The pedunculopomtine nucleus (PPN) is reciprocally connected to the BG. It input is from the globus pallidus interna, substantia nigra pars reticulata, and STN. Its output is glutamatergic to STN, GPOi, and SNC. It has been reported that in PD about 50% of its intrinsic cholinergic neurons are lost. Combined deep brain... 

Direct interstitial infusion has been applied to the treatment of patients with advanced Parkinson s disease, and the design of the protocol is instructive (29). Motor control is severely compromised in these patients because degradation of the substantia nigra ultimately results in massive overinhibition of the motor cortex by the globus pallidus interna (Gpi). One therapeutic approach is to thermally ablate a portion of the Gpi to reduce this inhibition and restore freedom of movement. However, thermal ablation also risks destroying the optic nerve that forms the floor of the Gpi structure. Hence, a chemical means of destroying the Gpi has been evaluated as a potentially more selective alternative. 

FIGURE 9.17 Relative interstitial concentration of quinolinic acid computed for a 5-yiL infusion at 0.1 [xL/min of an isotonic 50 mM solution into the globus pallidus interna of a primate (50-min infusion time). The horizontal dotted line represents the threshold concentration in relative units. Solid line curves denote profiles generated at the indicated times (minutes) during the infusion dashed line curves denote the profiles during the postinfusion period, where the numbers are minutes after the initiation of infusion. (Reproduced from Lonser RR et al. J Neurosurg 1999 91 294-302.)... 

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