An apparatus for treating the brain, comprises a first fluid delivery device including a distal end sized and shaped for placement at a first target site between a dura mater and a pia mater of the brain, the first fluid delivery device including a first fluid lumen extending to a first outlet port in the distal end to deliver fluids to a first target location and a first microelectrode mounted within the distal end of the first fluid delivery device for movement between an insertion position in which a first distal tip of the first microelectrode is received within the first fluid delivery device and a deployed position in which the first microelectrode extends out of the first fluid delivery device with the first distal tip thereof penetrating the pia mater to a first electrode target position in the cerebral cortex.