1. A probe device for electrical stimulation and recording of activity of excitable cells in brain tissue, the probe device comprising: a flexible substrate having a first area and comprising an exterior planar surface, wherein the flexible substrate is shaped to minimize brain tissue damage; a semiconductor die having a second area smaller than the first area and positioned on the exterior planar surface; and an array of pixels formed on the semiconductor die, wherein each pixel comprises at least one stimulation means and at least one recording means.