Multichip parallel integrated artificial vision for brain interface

点击翻译按钮获取中文摘要

The visual cortical prosthesis is the electronic device implanted in the visual cortex of blind patients to interface image signal to the cortical circuit in order to restore vision, even partially. Electrical stimulations provided by the electrodes implanted in the visual cortex are to be designed so as to evoke visual perception effectively in blind patients. The purpose of this study is to design the neuromorphic vision sensor that can be utilized as a visual cortical prosthesis. In human, the image is first pre-processed by the retina and then transmitted in parallel mainly to the primary visual cortex, or V1. On this physiological background, we have designed and fabricated a mixed analog-digital neuromorphic VLSI sensor that emulates the architecture and function of the retina and V1. The chip mimics light-induced responses of cortical simple cells in real time with extremely low power consumption, which are the most important assignments for visual prostheses. We also conducted physiological experiments studying effects of local current stimuli applied to the neuronal circuit of the mice cortical slices. Electrical response induced by bipolar current pulses applied to layer 4, which receives inputs from LGN, propagated vertically to layer 2/3. These observations suggested that the signal induced by the electrical stimuli propagated in the cortical circuit along the columnar structure of the visual cortex, in consistent with previous physiological and anatomical observations. We concluded that the neuromorphic vision sensor is suitable to interface the visual signal to the electrode implanted in primary visual cortex mimicking the inputs to V1 from LGN.