Brightening prospects for understanding the neural coding of perceived luminance(Invited Lectures at the 27th Annual Meeting)

抄録

Along with color, depth and motion, brightness is a fundamental quality of vision, and understanding the neural mechanisms of brightness perception is a topic of intense interest and controversy, both historically and in contemporary vision research. With few exceptions, modern textbooks still promote the fiction that brightness induction (e.g., simultaneous brightness contrast) results from lateral inhibition in isotropic filters, such as the circularly-concentric fields found in the retina. However, because brightness induction occurs over visual angles far in excess of the dimensions of individual retinal receptive fields (up to 10 degrees visual angle), "fill-in" accounts of brightness were proposed based on cortical mechanisms. A second historical challenge to retinal accounts of brightness induction was White's effect, in which the brightness of mid-gray patches situated on the dark and bright bars of a square-wave grating was opposite to that predicted by the output of circularly-concentric receptive fields. White's effect was a watershed event which caused spatial filtering accounts of brightness to be abandoned, and encouraged the development of high-level theories of brightness perception based largely on Helmholtzian idea of "unconscious inference". Through 25 year of systematic analysis of the grating induction effect Barbara Blakeslee and I have developed a "second-generation" theory of brightness perception which is based on oriented multi-scale spatial filtering which incorporates well-known properties of early cortical processing such as contrast normalization. We have recently applied the ODOG model to evaluate "anchoring" as an explanation of lightness perception, with the goal of clarifying and synthesizing the understanding of brightness and lightness.