Two-dimensional multi-channel neural probes with electronic depth control

Multi-electrode arrays for in vivo neural recording are presented incorporating the principle of electronic depth control, i.e. an electronic selection of electrode locations along the probe shaft independently for multiple channels. Two-dimensional (2D) arrays are realized using a commercial CMOS process for the electronic circuits combined with post-CMOS micromachining for shaping the probes and electrode metallization. These 2D arrays can be further assembled into 3D arrays. Two-dimensional arrays with IrO_x metal finish show electrode impedances between 100 KΩ and 1 MΩ. In vivo tests demonstrate the capability to simultaneously record multi-unit activity in addition to local field potentials on all 32 available output channels of the probe combs. Electronic steering enabled some of the electrodes to record from cortical and others to record from thalamic sites in the rat. This new device significantly increases the amount of useful information that can be obtained from a single experiment.