The long-range goal of this research is to understand the cellular and molecular mechanisms that mediate the normal performance and adaptive plasticity of smooth eye movements. The optokinetic reflex (OKR) prevents blurred vision during self-motion by producing smooth eye movements that compensate for full field image motion. Neuronal mechanisms of plasticity enable the OKR to adapt in the face of development, trauma, and disease. Although the roles of particular classes of neurons to signal transformations and plasticity have been identified, little is understood about how cellular mechanisms contribute to the day-to-day performance and adaptive capabilities of the OKR and other smooth eye movements. The objective of the proposed research is to elucidate how cerebellar activity influences signaling and plasticity in distinct classes of brainstem neurons responsible for smooth eye movements. The central hypothesis is that cerebellar and visual pathway synapses onto vestibular nucleus and nucleus prepositus hypoglossi neurons are differentially responsible for rapid initiation vs maintained components of smooth eye movements. The proposed research will examine the influence of cerebellar activity on eye movements evoked by moving visual stimuli. Cellular and synaptic physiological experiments in brainstem slice preparations will examine the short and long term dynamics of cerebellar and visual synapses onto cerebellar recipient neurons, which mediate cerebellar influences on signaling and plasticity on smooth eye movements. Distinct classes of cerebellar target neurons will be identified by their axonal projections and patterns of cerebellar synaptic cell terminals. The influence of visual pathway and cerebellar synaptic activity will be examined in cerebellar target neurons in the vestibular and prepositus nuclei. These studies will provide foundations for targeted investigations of the molecular mechanisms that mediate smooth eye movements as well as for pharmacological treatments of cerebellar disorders and of oculomotor disorders that cause nystagmus.

Public Health Relevance

The goal of this project is to identify cellular mechanisms of eye movement performance and plasticity, with a particular focus on cerebellar influence over smooth eye movements that are critical for stabilizing images on the retina during self-motion. Cellular mechanistic analyses of visual and cerebellar control of eye movements are essential for developing therapeutic treatments both for cerebellar disorders including ataxias and neurodegenerative diseases as well as for devastating disorders of eye movements including nystagmus and consequent oscillopsia.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY011027-20
Application #
9360620
Study Section
Sensorimotor Integration Study Section (SMI)
Program Officer
Araj, Houmam H
Project Start
2016-09-30
Project End
2019-08-31
Budget Start
2017-09-01
Budget End
2018-08-31
Support Year
20
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Otolaryngology
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21205
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Kodama, Takashi; du Lac, Sascha (2016) Adaptive Acceleration of Visually Evoked Smooth Eye Movements in Mice. J Neurosci 36:6836-49
Ehmsen, Jeffrey T; Liu, Yong; Wang, Yue et al. (2016) The astrocytic transporter SLC7A10 (Asc-1) mediates glycinergic inhibition of spinal cord motor neurons. Sci Rep 6:35592
McElvain, Lauren E; Faulstich, Michael; Jeanne, James M et al. (2015) Implementation of linear sensory signaling via multiple coordinated mechanisms at central vestibular nerve synapses. Neuron 85:1132-44
Kodama, Takashi; Guerrero, Shiloh; Shin, Minyoung et al. (2012) Neuronal classification and marker gene identification via single-cell expression profiling of brainstem vestibular neurons subserving cerebellar learning. J Neurosci 32:7819-31
Kolkman, Kristine E; McElvain, Lauren E; du Lac, Sascha (2011) Diverse precerebellar neurons share similar intrinsic excitability. J Neurosci 31:16665-74
Shin, Minyoung; Moghadam, Setareh H; Sekirnjak, Chris et al. (2011) Multiple types of cerebellar target neurons and their circuitry in the vestibulo-ocular reflex. J Neurosci 31:10776-86
van Welie, Ingrid; du Lac, Sascha (2011) Bidirectional control of BK channel open probability by CAMKII and PKC in medial vestibular nucleus neurons. J Neurophysiol 105:1651-9
Kolkman, Kristine E; Moghadam, Setareh H; du Lac, Sascha (2011) Intrinsic physiology of identified neurons in the prepositus hypoglossi and medial vestibular nuclei. J Vestib Res 21:33-47
Gittis, Aryn H; Moghadam, Setareh H; du Lac, Sascha (2010) Mechanisms of sustained high firing rates in two classes of vestibular nucleus neurons: differential contributions of resurgent Na, Kv3, and BK currents. J Neurophysiol 104:1625-34

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