Control System of Optogenetic Visual Cortical Prosthesis

Abstract

The visual is important, and this complex and sophisticated system is also fragile and vulnerable to disease and trauma. For centuries, mankind has fought to defend its vision with many means, from refractive devices to drugs to surgery. However, until now, the nature of the nerve cells has prevented the restoration of sight loss. Visual neuroprostheses, particularly visual cortical prostheses, are a worthwhile direction to explore for sight restoration. As the visual signal processing area, the visual cortex can be directly activated by electrical, optical (optogenetic) or magnetic stimulation and steadily bring phosphenes - flashes of light like a pixel on a screen. This thesis presents the design of a control system for an optogenetic visual cortical prosthesis, comprising both hardware and software components. The controlsystem, situated subcutaneously away from neural tissues, features a microcontroller processing unit and a power management module at its core. It serves as an intermediary between the external headset and the internal neural probes, ensuring the stability of wireless power and data connections within this complex, distributed system. Such an arrangement is vital as it supports the dynamic management and operational allocation among numerous probes required for high-resolution neural stimulation. The software of control system consists of an image processing algorithm specialized to mimic the processing of the human retina, a compression algorithm to support high-speed transmission, and an allocation algorithm to decrease the peak spike current. The subcutaneous hardware consist of a microcontroller processing unit, a power management module, and a wireless power module. In addition to this, the design of a new flexible probe adapted to this system is also explored.