A flexible multichannel ECoG array with PEDOT-coated electrodes for minimally invasive recording and stimulation

Electrocorticographic (ECoG) electrode arrays with epidural placement allow establishing neural interfaces which promote investigation of complex distributed brain functions and development of neuroprosthetic systems while having reduced invasiveness in comparison to intracortical or subdural electrode placement. In this work, we present the design and fabrication of a flexible ECoG array with 202 closely spaced electrodes, each coated with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) for long-term recording and stimulation in two visual cortical areas of macaque monkeys. The layout of the array promotes smooth attachment to the curved surface of the brain. We confirm its recording functionality in vivo by estimating visual receptive fields for the individual electrodes.