The mammalian superior colliculus (SC) is a subcortical structure that integrates visual and other sensory information to initiate orienting movements of the eyes and head. A fundamental feature of SC organization is that the representations of sensory inputs and motor outputs are topographically arranged and aligned. While great progress has been made in understanding the development of the visual representation in the SC, how the motor maps are formed and aligned with the visual map remains unknown. In order to take advantage of the available genetic tools in mice, the investigators propose to perform a comprehensive investigation of the organization and development of motor maps in the mouse SC. First, electrical microstimulation will be conducted in the deep layers of the SC to evoke saccade-like rapid eye movements in mice. The topographic organization of the eye movement map will be revealed by systematically varying the stimulation sites in the SC and determining the amplitude and direction of the evoked movements. Single-unit recording will also be performed in the deep layers to determine how individual neurons encode eye movement direction and amplitude, and how such movement fields are mapped in the mouse SC. Second, the same experiments will be performed in mice deprived of visual experience from birth and in an existing transgenic mouse line that have altered visual maps in the SC. These experiments will determine whether visual inputs provide an instructive signal for motor map development and visuomotor alignment. Together, the proposed experiments will provide the first systematic mapping of the deep layers of the mouse SC and initiate studies on factors influencing sensorimotor development. These studies will have important implications for the understanding and potential treatment of human eye movement disorders and other diseases that result from miswiring of neuronal connections. 6

Public Health Relevance

Studying the developmental interactions between sensory and motor representations has important implications for the understanding and potential treatment of human disorders in sensorimotor systems. The long-term goal of our research is to reveal the development and function of precise connections between neurons in the nervous system. These studies are of great clinical importance because many neurological and psychiatric illnesses result from miswiring of neuronal connections during development, including seizure disorders, mental retardation, schizophrenia, and autism spectrum disorders.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21EY023060-01A1
Application #
8594491
Study Section
Special Emphasis Panel (ZRG1-IFCN-Q (02))
Program Officer
Steinmetz, Michael A
Project Start
2013-09-01
Project End
2015-08-31
Budget Start
2013-09-01
Budget End
2014-08-31
Support Year
1
Fiscal Year
2013
Total Cost
$231,750
Indirect Cost
$81,750
Name
Northwestern University at Chicago
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
160079455
City
Evanston
State
IL
Country
United States
Zip Code
60201