Neurosurgery for mental disorder: past and present

Carlyle Jacobsen and John Fulton, at Yale in the early and mid-1930s, investigated primate frontal lobe function. Following bilateral frontal lobecotomy, monkeys and chimpanzees developed a delayedresponse deficit, being unable to perform tasks when there was a significant delay between the stimulus and the required response. There were accom panying behavioural changes, with the animals becoming more placid and lethargic and losing their characteristic inquisitive initiative. They became distractible, with difficulty in maintaining an attention set. They had great difficulty in adapting to changes in the directions of an already learned task, tending to perseverate. Fulton and Jacobsen did experiments on two chimpanzees, Becky and Lucie, who were laboratory favourites. Lucie performed well on the delayedresponse tasks prior to surgery but afterwards made many errors and displayed frequent temper tantrums with the consequent delays in food reward. In contrast, Becky exhibited a 'neurotic' behaviour