Neuromorphic Motion Detection and Orientation Selectivity by Volatile Resistive Switching Memories

Motion detection is a primary visual function, crucial for the survival of animals in nature. Direction-selective (DS) neurons can be found in multiple locations in the visual neural system, both in the retina and in the visual cortex. For instance, the DS ganglion cell in the retina provides a real-time response to moving objects, which is much faster than the image recognition executed in the visual cortex. Such in-retina biological signal processing capability is enabled by the spatiotemporal correlation within different receptive fields of the DS ganglion cells. Taking inspiration from the biological DS ganglion cells in the retina, the motion detection is demonstrated in an artificial neural network made of volatile resistive switching devices with short-term memory effects. The motion detection arises from the spatiotemporal correlation between the adjacent excitatory and inhibitory receptive fields with short-term memory synapses, closely resembling the physiological response of DS ganglion cells in the retina. The work supports real-time neuromorphic processing of sensor data by exploiting the unique physics of innovative memory devices.