A 64-site multishank CMOS low-profile neural stimulating probe

This paper describes a low-profile micromachined CMOS probe for multisite stimulation and recording in the central nervous system. The probe uses flexible silicon interconnects to allow the signal processing portion of the probe to fold at right angles to the penetrating probe shanks, limiting the implanted profile above the cortex to less than 1 mm. The probe is designed to stimulate a 4 mm(3) volume of neural tissue with a spatial resolution of 400 mu m using 1000 mu m(2) electrode sites. Eight of the 64 sites on the probe can be driven simultaneously over a current range from -127 mu A to +127 mu A with 1 mu A resolution. An on-chip preamplifier allows the neural activity on any selected site to be recorded with an overall gain of 30 and bandwidth from 50 Hz to 9 kHz. The probe operates with a stimulus current linearity of 0.98 up to clock frequencies as high as 5 MHz and dissipates less than 15 mu A in standby from +/-5 V supplies.