Andrew Zimnik, PhD
Name of Institution:
Columbia University, New York, NY
Role of basal ganglia output in acquiring and executing complex motor skills
Dr. Zimnik is a postdoctoral fellow in the lab of Dr. Mark Churchland at the Zuckerman Institute at Columbia University. His research interests include the role of the basal ganglia in health and disease and the neural mechanisms underlying skill learning. Dr. Zimnik also completed his PhD training in the lab of Dr. Churchland, during which he investigated the cortical processes that generate movements in the healthy brain by recording the activity of individual neurons in non-human primates trained to perform complex reaching tasks. His current research seeks to determine how the cortico-basal ganglia circuit learns and produces precise motor output. This work combines high-density electrophysiologic recordings from non-human primates with theoretical predictions grounded in analysis of artificial neural networks.
In this project, we will determine the computational role basal ganglia output plays in the initial learning and production of new movements.
The basal ganglia is a subcortical structure that communicates heavily with a myriad of brain areas. While there is strong evidence that the symptoms of a number of movement disorders – Parkinson’s disease (PD), Huntington’s disease, Tourette syndrome – are driven by pathologic activity that originates within the basal ganglia, we do not yet know how this aberrant activity produces pathologic movement. This gap in our knowledge largely stems from a poor understanding of the role the basal ganglia plays in the healthy brain. By developing a better understanding of what the basal ganglia contributes to normal movement-related computations, we can better characterize, and correct, the pathologic activity that arises in PD.
We will train monkeys to perform a task that requires them to learn new arm movements. The monkeys will use a hand-held pedal to traverse a virtual track as quickly as possible in order to receive a juice reward. What makes this task challenging, is the fact that the relationship between the physical movement of the pedal and the monkey’s movement through the virtual world will change throughout an experimental session. For example, sometimes the monkey will need to pedal quickly at the top of the cycle, and slowly at the bottom in order to ‘move’ rapidly, and sometimes they will need to do the opposite; the monkey will need to discover efficient movements through trial and error. While they perform this task, we will record neural activity from two areas: the basal ganglia and motor cortex, a region that is known to generate motor commands. This task will allow us to characterize the relationship between basal ganglia output and the cortical computations that generate movement.
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
Our ability to reverse the motor symptoms of PD would be greatly improved by a better understanding of the basal ganglia’s computational role in the healthy brain. If we can characterize the normal function of the cortico-basal ganglia circuit, we can better develop pharmacologic and surgical treatments to restore that function.