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 for selective extension from the distal end of the elongated shaft; a microelectrode array film comprising a first portion coupled toward the distal end of the elongated shaft and a second portion coupled with the support cylinder, the microelectrode array film comprising a plurality of microelectrode film shafts disposed on each of the plurality of shafts, each of the plurality of microelectrode film shafts comprising a plurality of microelectrode elements, the microelectrode array film further comprising: a helical ribbon cable that separates the first portion of the microelectrode array film from the second portion of the microelectrode array film, the helical ribbon cable couples each of the plurality of microelectrode elements with a respective proximal contact pad; a planar substrate having an insulative layer; and a plurality of conductive traces disposed on the insulative layer; and a stylet removably disposed in the internal lumen and configured to contact the support cylinder to selectively extend the plurality of shafts during implantation.