The ROBOCAST project aims to develop ICT scientific methods and technologies which focus on robot assisted keyhole neurosurgery. A modular system, allowing a reduction of the footprint, will be developed with two robots and one active bio-mimetic probe, able to cooperate among themselves in a biomimetic sensory-motor integrated framework. A gross positioning 3-axes robot will support a miniature parallel robot holding the probe to be introduced through a "keyhole" opening into the skull of the patient. Optical trackers (tracking the end effector and the patient), an imaging endoscope camera, and electromagnetic position and force sensors (on the probe) will extend robot perception by providing the control system with position and force feedback from the operating tools, and with visual information of the surgical field. Path planning outside and inside the body will be autonomously proposed by the control system by processing of preoperative diagnostic information. The path inside the brain will be planned on the basis of a "risk atlas" reproducing a fuzzy representation of a brain atlas, relating structures to a "level of danger". Construction of the atlas will rely on cognitive learning, where the system will be able to provide the surgeon with explanations for any suggested action. Semi-autonomous plan updating, following unforeseen changes occurring during surgery and based on processing of information gathered intra-operatively (e.g. ultrasonic images), will be negotiated between the system and the surgeon, where the latter will be allowed to specify any additional constraints to the planner. Ex- ante- and final path plan inside and outside the body will thus stem from the interaction between the surgeon and the intelligent core of the system. The interface between the system and the user will require minimal interaction while providing maximum information i.e. an intuitive interface which relies on context-based interpretation of surgeon commands.