NCT06692920 is a basic science interventional study conducted by the University of Minnesota that aims to characterize the pathophysiological role of the pallido-thalamocortical motor pathway in Parkinson's disease. During standard DBS surgery, researchers simultaneously record brain activity from the DBS lead in the internal segment of the globus pallidus (GPi) and from an ECoG strip placed over the motor cortex to understand how these brain regions communicate and how this communication differs in PD["@nct"].
Trial Information
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Overview
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NCT06692920 is a basic science interventional study conducted by the University of Minnesota that aims to characterize the pathophysiological role of the pallido-thalamocortical motor pathway in Parkinson's disease. During standard DBS surgery, researchers simultaneously record brain activity from the DBS lead in the internal segment of the globus pallidus (GPi) and from an ECoG strip placed over the motor cortex to understand how these brain regions communicate and how this communication differs in PD["@nct"].
Trial Information
| Attribute | Details | |-----------|---------| | NCT Number | NCT06692920 | | Official Title | Characterizing the Pathophysiological Role of the Pallido-thalamocortical Motor Pathway in Parkinson's Disease | | Sponsor | University of Minnesota | | Principal Investigator | Joshua E Aman, MD | | Phase | Not Applicable (Basic Science) | | Study Type | Interventional | | Indication | Parkinson's Disease | | Status | RECRUITING | | Enrollment | 25 participants (estimated) | | Study Duration | December 2024 – December 2027 | | Location | University of Minnesota, Minneapolis, MN |
Background
The Pallido-thalamocortical Pathway
The pallido-thalamocortical motor pathway is a critical neural circuit connecting:
Globus Pallidus internus (GPi) → the output nucleus of the basal ganglia
Thalamus → the relay station to the cortex
Motor Cortex → the final destination controlling voluntary movement
In Parkinson's disease, this pathway becomes dysregulated due to dopaminergic neuron loss in the substantia nigra pars compacta, leading to:
Despite decades of DBS therapy for PD, the precise mechanisms by which stimulation improves motor symptoms remain incompletely understood. This study aims to:
Characterize how brain activity in the pallido-thalamocortical pathway differs in PD
Identify biomarkers that predict optimal stimulation locations
Understand how stimulation frequency and location affect pathway activation
Study Design
Interventional Procedures
This is a single-group, basic science study conducted during clinically indicated DBS surgery.
Intraoperative Setup
During DBS lead placement surgery:
DBS Lead Placement: Standard trajectory to GPi target
ECoG Strip Placement: FDA-approved ECoG strip placed through the same burr hole over the motor cortex (no additional holes)
Simultaneous Recording: Brain activity recorded from both locations simultaneously
Stimulation Conditions
The study compares two stimulation conditions:
| Condition | Description | |-----------|-------------| | High Coherence | Stimulation through the DBS contact whose electrical activity is MOST similar to motor cortex activity | | Low Coherence | Stimulation through the DBS contact whose electrical activity is LEAST similar to motor cortex activity |
Motor Tasks
During the mapping session, patients perform:
Motor tasks: finger-tapping, pronation/supination, joystick manipulation, reaching to targets
Cognitive tasks: working memory tasks, decision-making with reward stimuli
Outcome Measures
Primary Outcomes
| Measure | Description | Timeframe | |---------|-------------|-----------| | Pallido-thalamocortical pathway activation | Amount of activity in the pathway from stimulation, comparing high vs. low coherence conditions | Post-surgery (1 day) | | Bradykinesia correlation | Relationship between bradykinesia measures and total pathway activation | Post-surgery (1 day) |
Key Measurements
Movement preparation time: How long to get ready to move
Movement onset: How fast movement starts
Movement execution: How long to touch the target
Linear mixed-effects model: Statistical analysis considering multiple subjects and observations
Eligibility Criteria
Inclusion Criteria
Diagnosis of idiopathic Parkinson's disease
DBS surgery at University of Minnesota planned as part of routine clinical care
Age 21-75 years
Exclusion Criteria
Other significant neurological disorder that may confound PD-related neurophysiological changes
History of dementia
Post-operative complications or adverse effects (e.g., ON-stimulation dystonias) affecting safety or confounding the experiment
Pregnant women
Known research radiation exposure within the last year that would exceed safe limits when combined with intraoperative fluoroscopy
Scientific Rationale
Why This Approach?
Recording from both GPi and motor cortex simultaneously provides unique insights:
Network-level understanding: How the entire pathway functions, not just individual nodes
Coherence analysis: Identifying which DBS contacts have activity most similar to motor cortex
Personalized targeting: Using brain activity to guide stimulation rather than anatomical coordinates alone
Expected Insights
This research may reveal:
Biomarkers for optimal DBS contact selection
How coherence between GPi and motor cortex relates to motor symptoms