He coined the terms "leucotomy" and "psychosurgery". In the United Kingdom it became known as the standard Freeman-Watts prefrontal leucotomy. Prior to the leucotomy, the chimps engaged in typical behavior including throwing feces and fighting. Limbic leucotomy is a combination of subcaudate tractotomy and anterior cingulotomy. In July 1946, Walker underwent a leucotomy and was subsequently able to resume teaching.