What is the therapeutic mechanism of pedunculopontine nucleus stimulation in Parkinson's disease?

What is the therapeutic mechanism of pedunculopontine nucleus stimulation in Parkinson's disease? Neurobiol Dis. 2018 Jun 19;: Authors: Thevathasan W, Moro E Abstract Pedunculopontine nucleus (PPN) deep brain stimulation (DBS) is an experimental treatment for in Parkinson's disease (PD) which offers a fairly circumscribed benefit for gait freezing and perhaps balance impairment. The benefit on gait freezing is variable and typically incomplete, which may reflect that the clinical application is yet to be optimised or reflect a fundamental limitation of the therapeutic mechanism. Thus, a better understanding of the therapeutic mechanism of PPN DBS may guide the further development of this therapy. The available evidence supports that the PPN is underactive in PD due to a combination of both degeneration and excessive inhibition. Low frequency PPN DBS could enhance PPN network activity, perhaps via disinhibition. A clinical implication is that in some PD patients, the PPN may be too degenerate for PPN DBS to work. Reaction time studies report that PPN DBS mediates a very specific benefit on pre-programmed movement. This seems relevant to the pathophysiology of gait freezing, which can be argued to reflect impaired release of pre-programmed adjustments to locomotion. Thus, the benefit of PPN DBS on gait freezing could be akin to that mediated by external cues. Alpha band activity is a prominent finding in local field potential recording...
Source: Neurobiology of Disease - Category: Neurology Authors: Tags: Neurobiol Dis Source Type: research