https://j.ideasspread.org/index.php/mhs <p>Modern Health Science (MHS) is an international, double-blind peer-reviewed, open-access journal, published by IDEAS SPREAD INC. It publishes original research, applied, and educational articles in all areas of health science. It provides an academic platform for professionals and researchers to contribute innovative work in the field.<br>Authors are encouraged to submit complete, unpublished, original works that are not under review in any other journals.<br>The journal is published in both print and online versions. The online version is free access and download.</p> IDEAS SPREAD INC en-US Modern Health Science 2576-7291 <p>Copyright for this article is retained by the author(s), with first publication rights granted to the journal.<br>This is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/).</p> https://j.ideasspread.org/index.php/mhs/article/view/1486 <p><strong>Purpose</strong></p> <p>Ocular counter-roll has been thought to be an otolith-ocular reflex. However, there is a hypothesis that it is a semicircular canal (SCC) ocular reflex. This study aimed to validate whether ocular counter-roll can be explained by the SCC theory.</p> <p><strong>Methods</strong></p> <p>Experiment 1: Two springs with plastic balls (different turning radius) were fixed to a swivel chair and were rotated suddenly. Experiment 2: Subject was seated and the entire upper body was bent forward 60 degrees with the neck fixed. Experiment 3: Subject was seated, the head was twisted 45 degrees to the right and the entire upper body was bent forward 60 degrees with the neck fixed. Experiment 4 (roll rotation): Subject was asked to tilt his upper body 60 degrees to the left. Eye movements in the dark were observed and recorded using an infrared camera. In Experiments 2, 3 and 4, subjects were four healthy humans.</p> <p><strong>Results</strong></p> <p>Experiment 1: Immediately after the movement, the two balls moved tangentially. The ball on the outside spring moved more compared to the ball attached to the inside spring. Experiment 2: In all subjects, nystagmus was vertical. The direction was downward. Experiment 3: In all subjects, nystagmus was vertical/torsional. The direction was downward (torsional component was leftward). Experiment 4: In all subjects, nystagmus was torsional, and the direction was leftward.</p> <p><strong>Conclusion</strong></p> <p>Since the role of SCCs is to sense angular acceleration in all directions of 360 degrees in a coordinated manner, bilateral vertical SCCs are stimulated in roll rotation. Therefore, SCC theory can explain the generation of ocular counter-roll. We proposed the “difference of inertial forces” theory to explain the mechanism of vestibulo-ocular reflex.</p> Hiroaki Ichijo Hisako Ichijo ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2025-03-12 2025-03-12 8 2 p1 p1 10.30560/mhs.v8n2p1