This paper retraces the fundamental achievements of Geoffrey Knight (1906-1994), a British neurosurgeon and a pioneer in the field of psychosurgery. His career developed in the 1950s and 1960s, when-following the unregulated practice of frontal lobotomies-strong criticism arose in the medical community and in the general public against psychosurgery. Geoffrey Knight's clinical research focused on identifying new, selective targets to limit the side effects of psychosurgery while improving the outcome of patients affected by mental disorders. Following the example of William Beecher Scoville, he initially developed restricted orbital undercutting as a less invasive alternative to standard frontal lobotomy. He then developed stereotactic subcaudate tractotomy, with the use of an original stereotactic device. Knight stressed the importance of the anatomy and neurophysiology of the structures targeted in subcaudate tractotomy, with particular regard to the fibers connecting the anterior cingulate region, the amygdala, the orbitofrontal cortex, and the hypothalamus. Of interest, the role of these white matter connections has been recently recognized in deep brain stimulation for major depression and anorexia nervosa. This is perhaps the most enduring legacy of Knight to the field of psychosurgery. He refined frontal leucotomies by selecting a restricted target at the center of a network that plays a crucial role in controlling mood disorders. He then developed a safe, minimally invasive stereotactic operation to reach this target. His work, well ahead of his time, still represents a valid reference on which to build future clinical experience in the modern era of neuromodulation for psychiatric diseases.
Keywords: DBS = deep brain stimulation; Geoffrey Knight; SCG = subgenual cingulate gyrus; deep brain stimulation; depression; history; orbital undercutting; psychosurgery; subcaudate tractotomy.