White matter pathway and individual variability in human stereoacuity

November 19, 2018

[Abstract]

Researchers in the Center for Information and Neural Networks (CiNet), the National Institute of Information and Communications Technology (NICT, President: Hideyuki Tokuda, Ph.D.), and Osaka University (President: Shojiro Nishio, Ph.D.) have identified a human white matter pathway associated with individual variability in human stereoacuity. By combining neuroimaging and psychophysical measurements, we found that the neural tissue density of the white matter pathway, the vertical occipital fasciculus (VOF), correlated with the individual variability in stereoacuity. The VOF connects the dorsal and ventral visual areas involved in stereopsis. This finding is important to understand the neural basis of dysfunction in stereopsis.

[Background]

Seeing in the three-dimensional world, stereopsis, is an important visual function for our daily life. A series of previous studies have revealed that our stereopsis is established by neural processing of binocular disparity, which is the retinal image difference between the two eyes. A number of studies have investigated which brain regions are involved in such information processing. Understanding of the neural mechanisms underlying stereopsis is crucial not only for visual neuroscience but also for application in virtual reality systems.

There is one unanswered key question regarding stereopsis: why the ability of depth discrimination (stereoacuity) varies greatly among people. In fact, previous studies have reported a broad distribution of human stereoacuity. Although it is likely that such a difference is related to a difference in the neural systems, the neurobiological origin of such individual differences is unknown.

[Achievements]

In this study, researchers in NICT and Osaka University examined the neuronal basis of individual differences in stereoacuity by combining cutting-edge neuroimaging techniques and psychophysics. We specifically focused on white matter pathways connecting distant brain areas because previous studies have demonstrated multiple brain areas in the dorsal and ventral visual areas are involved in stereopsis. We first identified trajectories of major white matter pathways related to visual processing by analyzing a diffusion MRI dataset. We then quantified neural tissues in the white matter using a quantitative MRI method. Furthermore, we estimated the stereoacuity of each individual human participant in a psychophysical experiment.

As a result, we found that the group with good stereoacuity showed significantly higher neural tissue density along a specific white matter pathway, the vertical occipital fasciculus (VOF) in the right hemisphere, compared to the group with poor stereoacuity (See Figure 1). A functional MRI experiment revealed that the dorsal and ventral visual areas connected by the VOF are involved in stereopsis. Finally, we also confirmed that the neural tissue properties of the VOF did not correlate with performance in contrast detection, which does not require binocular integration of visual information. These results suggest that the communication between the dorsal and ventral visual brain areas via the VOF plays an important role in human stereopsis

[Future Perspective]

A previous study found that approximately 30% of healthy individuals have relatively lower performance in stereoacuity. Further research on stereoacuity and white matter will contribute to a method for improving our performance in stereopsis.
-end-
This paper appeared in the journal Proceedings of the National Academy of Sciences of the United States of America on November 15 (Japan Standard Time), 2018.

[Full Reference to the Paper]


Journal: Proceedings of the National Academy of Sciences of the United States of America. (2018) [Epub ahead of print]
URL: http://www.pnas.org/content/early/2018/11/13/1804741115
DOI: https://doi.org/10.1073/pnas.1804741115
Title: Microstructural properties of the vertical occipital fasciculus explain the variability in human stereoacuity Authors: Hiroki Oishi, Hiromasa Takemura, Shuntaro C. Aoki, Ichiro Fujita, and Kaoru Amano

National Institute of Information and Communications Technology (NICT)

Related White Matter Articles from Brightsurf:

'White matter lesion' mapping tool identifies early signs of dementia
A new tool for analyzing tissue damage seen on MRI brain scans can detect with more than 70% accuracy early signs of cognitive decline, new research shows.

What lies between grey and white in the brain
A multidisciplinary team led by Nikolaus Weiskopf from the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) has succeeded in making the superficial white matter visible in the living human brain.

Math test score gap between white and non-white students in Brazil due to complex factors
School test scores often show gaps in performance between white and non-white students.

Smoking may cause white scars on the brain
Nearly half of all people over the age of 50 have scarring in their brain's white matter.

Mapping white clover heritage
Pedigree analysis will help breeders develop clover varieties with desired traits.

White matter affects how people respond to brain stimulation therapy
Tiny changes in the microscopic structure of the human brain may affect how patients respond to an emerging therapy for neurological problems.

The Lancet Neurology: High blood pressure and rising blood pressure between ages 36-53 are associated with smaller brain volume and white matter lesions in later years
A study of the world's oldest, continuously-studied birth cohort tracked blood pressure from early adulthood through to late life and explored its influence on brain pathologies detected using brain scanning in their early 70s.

The ancestor of the great white shark
Mackerel sharks are a group consisting of some of the most iconic sharks we know, including the mako shark, the great white shark and Megalodon, the biggest predatory shark.

What is white chocolate? (video)
Today, we're showing our love for white chocolate. Sure, it lacks the rich flavor of milk chocolate and the glossy brown color of dark chocolate.

White matter pathway and individual variability in human stereoacuity
Researchers in the National Institute of Information and Communications Technology (NICT), and Osaka University have identified a human white matter pathway associated with individual variability in human stereoacuity.

Read More: White Matter News and White Matter Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.