Age-related changes of the cortical visual-vestibular interaction in healthy subjects [thesis]

Iskra Stefanova
The visual and vestibular systems play one of the central roles in the perception of verticality, spatial orientation, maintenance of balance and distinguishing self-motion from motion of the environment. As the brain continuously and simultaneously receives an enormous quantity of information through their receptor organs, collaboration between these systems at different levels of information processing is crucial for the proper execution of the above mentioned functions. Psychophysical and
more » ... roimaging research in humans has provided support for the concept of a reciprocal inhibitory visual-vestibular interaction, the functional significance of which lies in suppression of potential mismatch between incongruent sensory inputs delivered from the two systems. Functional magnetic resonance imaging (fMRI) enabled visualization of this interaction through detection of blood-oxygen-level-dependant (BOLD) signal increases or signal decreases in the visual and vestibular networks during unisensory stimulation. Specifically, visual stimulation related to the percept of self-motion, such as optokinetic stimulation, was shown to elicit BOLD signal increases in areas involved in visual processing along with BOLD signal decreases in areas involved in vestibular processing. Increasing age was shown to alter the morphological and functional properties of the sensory, motor and cognitive systems. Previous research has revealed that senescence associates with deterioration of both, visual and vestibular functions, as well as a change in the psychophysical measurements related to their interaction. However, the effects of age on the BOLD signal pattern reflecting the visual-vestibular interaction have not yet been investigated. Exploring these effects in healthy subjects could offer the possibility to detect early age-related changes in the cortical function occurring before a decline in behavioural measurements can be detected. Aside broadening the scientific knowledge on the physiological changes with age in the sensory system [...]
doi:10.5282/edoc.15321 fatcat:lmvh476wevhsjovxmkrrglhwom