RECORDING NEURAL ACTIVITY IN THE HONEYBEE BRAIN WITH MICROMACHINED SILICON SENSORS

A 12-channel probe has been machined in silicon using a boron etch-stop technique to define a substrate of 20 μm in thickness, tapering from 2 mm in width through 150 μm to a pointed tip. The part of the probe carrying the sensory terminals is 800 μm in length. Each sensory terminal consists of a 4-μm diameter well exposed over a polysilicon conductor. The sensory terminals are aligned at 50-μm intervals. This probe has been used to monitor in vivo neuronal activity in the honeybee brain, where simultaneous recordings are required from spatially discrete populations of cells. The outputs of the array are illustrated along with a computerised, colourgraphic atlas that was used to define the recording loci. In this atlas, each 1000 μm3 of brain tissue is represented by an 8-bit, 1-byte unit in a 3-D graphic array of 5.6 megabytes. © 1990.