# Dissecting the inhibitory architecture governing basal ganglia output

> **NIH NIH R00** · GEORGETOWN UNIVERSITY · 2022 · $59,222

## Abstract

Abstract. The subthalamic nucleus (STN) is part of the basal ganglia. It plays a role in motor
behavior through its connections with the globus pallidus, substantia nigra, and possibly through
direct connections with the pedunculopontine nucleus (PPN). Retrograde labeling shows that the
STN synapses onto PPN neurons, but it is unclear whether this connection has a functional role
in motor output. Because both the STN and PPN are targeted in deep brain stimulation to alleviate
motor symptoms in degenerative disorders, understanding their connectivity will yield deeper
insights into the circuit mechanisms of motor control. Using in vivo optogenetic stimulation, we
will directly test the behavioral effects of activating this connection. Specifically, we will infect STN
neurons with channelrhodopsin and activate STN axons via a fiber implanted above the PPN. We
will activate this circuit in freely-moving mice, during motor skill learning, and during a challenging
balance task. While stimulating the STN input onto the substantia nigra inhibits motion, we
hypothesize that stimulating the STN-PPN connection will modulate locomotion, balance, and
motor learning. This hypothesis is based on previous findings that the STN sends excitatory inputs
to the PPN and that direct stimulation of STN cell bodies affects motion and motor skill
learning. This project will yield a better understanding of the functional relationship between the
STN and the PPN and is the first step toward developing more specific deep brain stimulation
treatments.

## Key facts

- **NIH application ID:** 10536523
- **Project number:** 3R00NS112417-03S1
- **Recipient organization:** GEORGETOWN UNIVERSITY
- **Principal Investigator:** Rebekah Coleman Evans
- **Activity code:** R00 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $59,222
- **Award type:** 3
- **Project period:** 2019-09-01 → 2024-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10536523

## Citation

> US National Institutes of Health, RePORTER application 10536523, Dissecting the inhibitory architecture governing basal ganglia output (3R00NS112417-03S1). Retrieved via AI Analytics 2026-06-02 from https://api.ai-analytics.org/grant/nih/10536523. Licensed CC0.

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