Brain changes as a consequence of blindness in one half of the visual field

Even though there is increasing interest in the reorganisation of the brain after vision loss, systemic investigation of neuroplasticity in patients with homonymous hemianopia (HH), the complete loss of one side of the visual field, is still very rare. Better understanding of this unchartered field has tremendous potential for the development or neuroscientifically-motivated rehabilitation techniques. For that reason and with this project, I want to get insight into whether and how both the visual and the auditory system reorganise after acquiring HH. More specifically, I want to investigate adaptive auditory and visual processing (optimised residual and risen compensatory perceptual performance) of patients with HH and I expect this to be reflected in cortical reorganisation at both a structural and a functional level. For this purpose psychophysical tests will be performed and cortical plasticity will be assed by (f)MRI using a combination of a novel techniques (i.e. population receptive field modelling, connective field mapping and cortical thickness comparisons). In this way, the impact of homonymous visual field defects on perceptual processing can be investigated and, subsequently, the degree of optimised residual and compensatory perceptual behaviour can be correlated with structural and functional cortical plasticity. This provides us with new quantitative knowledge about changes in cortical structure, visual and auditory networks and maps in HH close to the level of neuronal populations – the level that is most critical for understanding the relationship between neural computations, behaviour and perception, which could eventually lead to systematic training tools that will improve the reorganisation.

We expect to find adaptive auditory and visual processing (optimised residual and risen compensatory perceptual performance) as a consequence of homonymous hemianopia. Additionally, we hypothesise these changes to be reflected in sustained functional and structural changes on the cortical level. More specifically, we expect a) remapped visual field representations in the visual cortex, b) structural changes in the visual system (i.e. cortical thickness and white matter tracts), c) changes in cortical representations of auditory space, and d) changes in functional connectivity maps.

not applicable, no longitudinal design

auditory and visual functioning tests
(f)MRI measurements