Neurovascular coupling reflex - Contralateral stimulation apparatus and setup

Neurovascular coupling (NVC) in the brain is well studied and is one of the physical stimulation responses triggered by the central nervous system. NVC, or functional hyperemia, is described as the local blood flow increase due to the release of vasodilator chemicals from neuronal cells into vessels. This behavior also exists in the retinal vasculature. However, it was only measured in the ipsilateral retina. Assessing photic stimulation in the contralateral retina can shed light on retina-retina or brain-retina neural pathways. Emerging technologies provide new ways of measuring this effect with high spatial and temporal resolution. Adaptive optics has been used in astronomy with great results. Yet, implementing this technology in retinal fundus imaging was revolutionary in providing extremely high spatial resolution images. The RTX1 ™ is an adaptive optics retinal camera capable of ipsilateral light flicker to stimulate photoreceptors and document the induced response. The NVC in the ipsilateral retina has been successfully assessed using this equipment. Using the RTX1™ with an external flickering device, it is possible to explore contralateral stimulation's effects. The first preliminary tests show a full working prototype (contralateral stimulation) with successful software integration into the RTX1TM. A set of images was acquired to fully document the entire procedure and evaluate all components. Further evaluation will be necessary to optimize flicker-related parameters in the quest for the ipsilateral NV C response.