EASTBIO Understanding the principles for combining redundant information from the two eyes

Motor ocular dominance or eyedness is the preference for one of the two eyes when sighting. This preference is typically stable when tested under standard conditions. Eyedness guides decisions about which eye to rely on in sports like golf or baseball. Eye-care professionals use it to correct age-related far-sightedness in people who are already near-sighted: they will likely determine the non-dominant eye and correct it to see close-up objects, while the dominant eye will be corrected to see in the distance. Hardly anything is known about how eyedness emerges and its role in normal vision. A renewed interest in this topic was sparked by the findings of a weaker eye dominance in individuals with dyslexia compared with neurotypicals.

The dominant eye is not necessarily the eye with the best visual acuity. A sensory modality that has so far been overlooked by this research is oculoproprioception. Stretch receptors within the extraocular muscles inform the brain about the movement of the eyes in the orbits. This sensory modality can tell whether the movement of visual stimuli on the retina is caused by own eye movements or is externally produced. It is notoriously difficult to interfere with this sensory modality in a controlled way. Transcranial magnetic stimulation (TMS) over the representation of the contralateral eye in the somatosensory cortex has now been validated as a method to alter oculoproprioception in humans. We will use this method here.

The two eyes often provide the same information to the brain, such as for instance the direction of motion of a visual object on a computer screen. A hypothesis is that eyedness reflects a preference for the most reliable sensory information. In computational modelling on the combination of two or more signals, a theory states that when two channels provide the same information about an object, this overlapping information is combined in the most efficient way by weighting each channel according to its reliability. With this, the combination is more reliable than what would be expected from each individual signal alone. This theory has been applied successfully to understand how two sensory modalities are combined. Our objective is to find out whether it also explains how the brain integrates information from the two eyes.

The successful candidate will join a group of vision researchers at the University of St Andrews. S/he will gain experience in visual psychophysics, transcranial magnetic stimulation, and computational modelling in both neurotypical individuals and people with dyslexia.

HOW TO APPLY

Application instructions can be found on the EASTBIO website- http://www.eastscotbiodtp.ac.uk/how-apply-0

1)     Download and complete the Equality, Diversity and Inclusion survey.

2)     Download and complete the EASTBIO Application Form.

3)     Submit an application to St Andrews University through the Online Application Portal

Your online application must include the following documents:

-         Completed EASTBIO application form

-         2 References (to be completed on the EASTBIO Reference Form, also found on the EASTBIO website)

-         Academic Qualifications

-         English Language Qualification (if applicable)

Unfortunately due to workload constraints, we cannot consider incomplete applications. Please make sure your application is complete by 27^th November 2023

CONTACT

Queries on the project can be directed to the project supervisor.

Queries on the application process can be directed to Rachel Horn at [Email Address Removed]

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