Binocular rivalry and interocular grouping characteristics in participants within the autism spectrum condition
Studies on binocular functions of individuals within the autism spectrum (AS) showed greater proportions of binocular vision disorders, e.g. higher prevalence of strabismus (‘squinting’), amblyopia (‘lazy eye’) as well as poorer depth perception compared to non-autistic populations. Our interdisciplinary project, integrating aspects of vision- and neuroscience, aims to investigate the binocularity of individuals within the AS. We will carry out a comprehensive set of optometric tests to examine whether AS participants have regular binocular vision and if so, investigate visual perception during both a binocular rivalry (i.e. interocular competition of perception) and an interocular grouping paradigm (i.e. interocular combination of perception). We will investigate visual suppression and various mixed as well as interocularly grouped perceptual states during those paradigms that are thought to be processed in binocular brain areas. This project will improve our understanding of binocular vision functions in the AS population and may serve to develop a clinical investigation and monitoring tool to assess the binocularity of individuals within the AS.
Samantha L. STRONG - School of Optometry and Vision Science, Université de Bradford
Vision can only be considered successful if we achieve a conscious percept of our visual environment which relies on successful cortical (neural) processing of the retinal signals in the brain.
The human brain processes visual information by means of separating out each aspect of the signal from the retina (i.e. colour, form, direction) and using specialised populations of neurons to interpret these individual features before combining the information to create a complete perception. This is called the ‘functional specialization’ of the visual cortex.
In humans, there is a vast network of areas within the brain that are responsible for processing moving objects in our visual field which not only enables successful manoeuvring of the self through the environment, but also has evolutionary advantages for alerting us to dynamic dangers.
The main aim of this project will be to investigate the bilateral differences between visual motion-sensitive areas in the human brain, focusing on an area called V5/MT+ and its smaller subdivisions (MT and MST) across both hemispheres. To investigate this, motion-sensitive areas within human participants will be identified in a functional magnetic resonance imaging (fMRI) scanner. These data will then be analysed and transcranial magnetic stimulation (TMS) will be applied to each motion-sensitive area. Application of TMS temporarily disrupts normal cortical functioning so if there is a behavioural consequence, it is possible to conclude that the targeted brain area is important for the designated task. If there are differences in disruption between brain areas or across hemispheres then this will help to determine how the brain is processing these visual signals.
- François DANIEL
- Arnaud FOISY
- Zoi KAPOULA