Photosynthetic protein-based simple cell receptive fields for detection of Café Wall illusions

The differential response of the photosynthetic protein bacteriorhodopsin (bR) is highlighted as a means to emulate excitation and inhibition in neural response. We present a neuromorphic device that mimics a simple cell receptive field fabricated by patterning bR onto two transparent electrodes and sealing them with an electrolyte solution. The artificial receptive field is characterised as a bandpass filter that simultaneously emulates excitation and inhibition with a single element, requiring no bias power supply or external operating circuitry. The filter was employed to detect the Café Wall illusion, a type of orientation illusion, and demonstrated its ability to replicate the human eye’s perception using only the properties of the protein.