Advisory Committee Chair
Claudio Busettini
Advisory Committee Members
Roderick J Fullard
Paul D Gamlin
Timothy J Gawne
Kristina M Visscher
Document Type
Dissertation
Date of Award
2011
Degree Name by School
Doctor of Philosophy (PhD) School of Optometry
Abstract
A long standing debate regarding the neural organization of oculomotor control began in the late 1800's with Hering and von Helmholtz proposing two opposing ideologies. Von Helmholtz proposed a monocular structure of the oculomotor circuitry in which each eye receives separate motor commands. Hering offered his law of equal innervation, which states that all eye movements are the sum of binocular vergence and conjugate commands. As a test of Hering's binocular proposal, this project compared the behavior of midbrain vergence cells during: 1) saccade-free stepwise transfers of gaze in depth; 2) combined saccade-vergence eye movements; 3) pure vergence tracking, and 4) smooth tracking in depth along oblique directions in space. Hering's law of equal innervation requires that vergence cell firing would remain consistent whether the movement is a pure vergence movement or a combination of vergence and conjugate commands. For this project, the perturbing conjugate commands of the first experiment were saccades, and smooth pursuit was introduced in the second experiment. Evidence for the majority of midbrain vergence cells to encode only part of the vergence response during these interactions directly challenges Hering's law of equal innervation.
Recommended Citation
Corthell, Leah, "Behavior Of Midbrain Vergence Cells During Stepwise Transfers Of Gaze And Oblique Tracking In Depth" (2011). All ETDs from UAB. 1422.
https://digitalcommons.library.uab.edu/etd-collection/1422