# Disparity processing in human visual cortex

> **NIH NIH R01** · STANFORD UNIVERSITY · 2020 · $412,373

## Abstract

The fact that we view the world through two eyes provides us with the computational basis for exquisite sensitivity
to the structure and layout of the three-dimensional world. This sensitivity is derived, in large part, through a
combination of retinal disparity and motion cues. Our understanding of the computations and cortical
mechanisms that underlie mature depth perception is still rudimentary and there is a lack of neural developmental
data regarding sensitivity to depth cues outside of the earliest visual areas and youngest ages. In the first Aim,
dynamic random dot stereograms will be used to measure the complete developmental sequence for a critical
performance limit of the stereoscopic visual system – the minimal disparity that can be detected (stereoacuity).
These limits will be measured in developing infants, children and adults using Steady-state Visual Evoked
Potentials and will be related to measurements of spatial contrast sensitivity in the same participants. The
comparison will allow us to determine whether low-level stimulus visibility is the critical limiting factor in the
development of stereopsis or whether more central limits are involved. In the second Aim, sensitivity to binocular
motion cues will be studied across development, as these cues provide independent information for scene layout
and may involve mechanisms different from those responsible for coding binocular disparity. Preliminary data
suggest that a binocular motion mechanism sensitive to differences in velocity between the two eyes that is
present in the adult is absent in infants. This Aim will provide the complete developmental sequence for this
system and will determine its relationship to monocular motion sensitivity. The third Aim will use functional
Magnetic Resonance Imaging (fMRI) to localize disparity and binocular-motion-related activity within identified
visual areas of the healthy adult visual system. These data will provide evidence regarding opponent binocular
mechanisms we hypothesize form the foundation of figure-ground segmentation/depth estimation and that are
selectively immature in infancy. The fMRI data will also identify areas most likely to support the perception of
depth from disparity and binocular motion cues. The data sets we will provide will be the first functional
measurements of the development of sensitivity to disparity, motion and contrast made using a consistent and
sensitive methodology throughout the development of key mechanisms of spatial vision. This research
addresses fundamental questions about how changes in cortical response organization over human visual
development allow the visual system to encode the spatial layout of the environment. The timing of the maturation
sequences of these processes is directly relevant to developmental disorders of visual processing – especially
strabismus and amblyopia. Importantly, the methods used here to study normal visual development are readily
adaptable for use in clinical resea...

## Key facts

- **NIH application ID:** 9968237
- **Project number:** 5R01EY018875-10
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** ANTHONY M NORCIA
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $412,373
- **Award type:** 5
- **Project period:** 2008-08-01 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9968237

## Citation

> US National Institutes of Health, RePORTER application 9968237, Disparity processing in human visual cortex (5R01EY018875-10). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9968237. Licensed CC0.

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