During a flight controls check prior to take-off, the aircraft experienced an apparent binding of the elevator control system at a location just forward of the aft stop. The flight was aborted and the aircraft returned to the gate for further investigation. Maintenance personnel carried out further investigation into the control system, to include a complete operational check of the elevator control system. The subsequent checks completed both powered and unpowered revealed none of the ratcheting and binding reported by the flight crew. After a thorough check the aircraft was returned to service.