# Neurophysiology of Disjunctive Saccades

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 2024 · $748,230

## Abstract

ABSTRACT
 For more than 100 years much of oculomotor research in primates has been guided by Hering's law, which
states that any eye movement generated by the brain will be sent equally to the two eyes so that they move as
a yoked pair. Refixations between targets in different directions involve saccades, which are conjugate
movements that have peak velocities of hundreds of degrees per second. Refixations between targets at different
distances require vergence eye movements, which slowly rotate the eyes by equal amounts in opposite
directions. For gaze shifts between targets that differ in both direction and distance, vergence velocity is
substantially higher during the saccade. The neural basis for this effect has been the subject of intense debate
for more than 35 years. According to one view, consistent with Hering's Law, the extremely high intrasaccaddic
vergence velocity results from a non-linear interaction between saccades and vergence. Alternatively, the
vergence angle changes rapidly during the saccade because the saccadic system programs unequal saccades.
This latter view would be inconsistent with Hering's law, since it necessitates the generation of unequal saccadic
commands. For this reason, virtually all of the relevant neurophysiological studies have targeted brain areas
involved in the generation of saccadic eye movements. The existing literature has yielded conflicting results,
which is why this problem remains controversial. The experiments in this proposal take a novel approach,
primarily by targeting brain areas involved in the generation of vergence eye movements during both slow
vergence and disjunctive saccades.

## Key facts

- **NIH application ID:** 10811933
- **Project number:** 1R01EY035921-01
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Mark M Walton
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $748,230
- **Award type:** 1
- **Project period:** 2024-06-01 → 2029-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10811933

## Citation

> US National Institutes of Health, RePORTER application 10811933, Neurophysiology of Disjunctive Saccades (1R01EY035921-01). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10811933. Licensed CC0.

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