1. An implantable neurological probe comprising: an elongated shaft having a distal end and an internal lumen; a support cylinder slidingly disposed in only a distal portion of the internal lumen; a plurality of shafts coupled to the support cylinder and arranged to be selectively extended from the distal end of the elongated shaft; a plurality of microelectrode elements disposed on each of the plurality of shafts, the microelectrode elements comprising a planar substrate having an insulative layer and a plurality of conductive traces disposed on the insulative layer, a stylet removably disposed in the internal lumen and configured to contact the support cylinder to selectively extend the plurality of shafts during implantation; and a pull wire coupled to the support cylinder to selectively retract the support cylinder and plurality of shafts within the internal lumen.