Analog VLSI-based Modeling of the Primate Oculomotor System

T. Horiuchi & C. Koch
Neural Computation Journal (in press)

Abstract:

One way to understand a neurobiological system is by building a simulacrum that replicates its behavior in real-time using similar constraints. Analog {\bf V}ery {\bf L}arge {\bf S}cale {\bf I}ntegrated (VLSI) electronic circuit technology provides such an enabling technology. We here describe a neuromorphic system that is part of a long-term effort to understand the primate oculomotor system. It requires both fast sensory processing as well as fast motor control to interact with the world. A one-dimensional hardware model of the primate eye has been built which simulates the physical dynamics of the biological system. It is driven by two different analog VLSI chips, one mimicking cortical visual processing for target selection and tracking and another modeling brainstem circuits that drive the eye muscles. Our oculomotor plant demonstrates both smooth pursuit movements, driven by a retinal velocity error signal, as well as saccadic eye movements, controlled by retinal position error, and can reproduce several behavioral, stimulation, lesion, and adaptation experiments performed on primates.