Parkinson's Disease Foundation

Parkinson's Disease Foundation is using its 2017 distribution to fund:

Role of cerebellum on basal ganglia cortical network in Parkinson's disease

PROJECT TITLE:  Role of cerebellum on basal ganglia cortical network in Parkinson's disease

Investigators/Authors: Nicholas Strzalkowski, Ph.D.; mentor Zelma Kiss M.D., Ph.D., University of Calgary

Objective: The purpose of the present study is to investigate the role of the cerebellum in modulating basal ganglia and cortical activity, and its relationship to Parkinsonian tremor.

Background:
In Parkinson’s disease (PD) there are abnormalities in brain regions important in the control of voluntary movement. The purpose of this project is to learn the relationship between three of these brain regions: the basal ganglia, motor cortex, and cerebellum in PD patients who have undergone deep brain stimulation (DBS) treatment. DBS involves the implantation of electrodes (wires) into the basal ganglia. In our center, we externalize the DBS electrodes for a few days after surgery, providing a unique opportunity to record basal ganglia activity.

Methods/Design:
We will record signals from the electrodes implanted into basal ganglia of DBS patients. We will also record signals from the motor cortex using electrodes placed on the scalp (EEG). These deep (basal ganglia) and surface (motor cortex) brain recordings will be compared before and after the cerebellum is temporarily shut down through a noninvasive technique called continuous theta burst stimulation (cTBS). The cerebellum is thought to be involved in tremor and to explore this relationship, we will measure arm movement changes in response to cerebellar cTBS.

Relevance to Diagnosis/Treatment of Parkinson’s disease:
Altering cerebellar function through cTBS has been proposed as a therapeutic treatment for PD. This work has potential to contribute to the development of non-invasive treatment options for PD patients by improving our understanding of the role of the cerebellum in PD.

September 2018 Project Update:

The overall goal of the project is to better understand the relationship between cerebellum activity and the pathology/symptoms of Parkinson's disease. In the first year of the project, we conducted a preliminary study, now published in the journal The Cerebellum, to investigate the effectiveness of two different transcranial magnetic stimulation (TMS) protocols in depressing (reducing) cerebellar activity in healthy control subjects. We found that both protocols were equally effective in depressing activity of the cerebellum. This finding gave us confidence to move forward in applying the traditional TMS protocol on Parkinson's patients. To date we have used the technique to depress the cerebellum of three PD patients with subthalamic nucleus (STN) deep brain stimulation (DBS), and one essential tremor DBS patient. We recorded the neuron firing patterns from the DBS electrodes and from the scalp with surface electrodes before and after depressing activity in the cerebellum with TMS. Preliminary data suggests that in PD the cerebellum may in fact play a compensatory role, helping to suppress neural activity associated with motor symptoms. These findings go against our initial hypothesis that the cerebellum contributes to the pathology of PD. We are continuing to recruit patients and collect data to pursue this topic further.

September 2019 Project Update:

Dr. Strzalkowski received a Faculty position last summer, and therefore is no longer eligible for funding form the Parkinson’s Foundation.