Retinale Implantate

Projekt P4: Enhancing spatial and temporal resolution or electrical retinal implants by implantation of feature-based biomimetic stimulation

01/05/2021 to 30/04/2023

The primary task of this project is the establishment of a novel experimental setup to investigate the potential of feature-based biomimetic stimulation for retinal e-implants. The concept of MEIs based retinal stimulation has been explored on healthy retina by light-stimulation (Euler lab, work in progress), hence herein we aim to translate the method for e-stimulation based MEIs (eMEIs). On the other hand, the saccade mimicking activation of e-electrodes has been investigated in epiretinal configuration (Haq lab), hence herein we aim to adapt the method for subretinal e-stimulation. However, the integration and realization of both methods requires the so-called sandwich-experiments: multi-electrode subretinal e-stimulation and simultaneous multi-electrode epiretinal recordings of ganglion cell spikes. The proof of concept for such experiments has been elaborated previously by Stutzki et al (2016) and Haq et al (2018) employing single electrodes or large field multi-electrode array with 100 µm electrode spacing. Herein we envision to employ dense multi-electrode array for e-stimulation (custom made, cooperation partner or special commercial order) and recoding (commercially available) with smaller electrode size of 10 µm and denser 40 µm electrode spacing. The proposed electrode configuration increases the experimental complexity, but it is crucial to correlate the e-stimulation with the evoked responses at high temporal and spatial resolution. Moreover, high-resolution calcium imaging (e.g. 2-Photon imaging) will be combined to investigate cellular and synaptic resolution in the various retinal layers (e.g. amacrine cells).