IIRC G-Loc (Gravity induced loss of consciousness) and Cognitive Impairment where two terms introduced during the late 1980's/early 90's when rules and a better understanding around the subject of "Human Factors" were being established/revised. At that time I was a member of the Applied Psychology Dept. of the College of Space and Aeronautics at Cranfield Institute of Technology and was involved on the periphery of the discussions. Which I might add were at times quite heated and particularly over the term Cognitive Impairment (CI). This was because I seem to remember CI was seen as a bucket term to cover many different physical/mental conditions which could affect the efficiency of a pilot to function effectively.
IIRC the whole of this programme was under the auspices of the CAA rather than the RAF but I could be wrong.