Multichip parallel integrated artificial vision for brain interface

视皮层假体是植入盲人视皮层的电子装置，用于将图像信号连接到皮层回路，以恢复视力，甚至部分恢复视力。由植入视觉皮层的电极提供的电刺激应设计为有效地唤起盲人患者的视觉感知。本研究的目的是设计一种可以作为视觉皮层假体的神经形态视觉传感器。在人类中，图像首先由视网膜进行预处理，然后主要并行传输到初级视觉皮层或V1。在此生理背景下，我们设计并制作了一个模拟数字混合的神经形态VLSI传感器，模拟视网膜和V1的结构和功能。该芯片能够以极低的功耗真实的实时模拟皮层简单细胞的光诱导反应，这是视觉假体最重要的任务。我们还进行了生理实验，研究局部电流刺激施加到小鼠皮层切片的神经元回路的影响。由施加到层4的双极电流脉冲引起的电响应，其接收来自LGN的输入，垂直传播到层2/3。这些观察结果表明，由电刺激引起的信号在皮层回路中沿着视皮层的柱状结构传播，与先前的生理和解剖观察结果一致。我们的结论是，神经形态视觉传感器是适合接口的视觉信号植入在初级视觉皮层模仿输入到V1从LGN的电极。

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.