SM was born in 1965 and suffered from acute epileptic seizures. Initially, it was believed that he had a cerebral tumor which caused epilepsy. However, the medical team found that the seizures were generated by bilateral atrophy within the medial temporal lobe, specifically in the amygdala.
From an early age, SM did not recognize fear. This lack of emotional response led researchers to study his brain to understand how fear is processed. In 2010, they exposed SM to live snakes and spiders, took him on a tour of a haunted house, and showed him horror movies. When asked to draw fear, SM would draw a crawling baby. This research placed fear in the brain and showed that it is not just an emotion but also a physiological response that can be studied scientifically.
SM suffered from Urbach-Wiethe disease, which induced the formation of calcium deposits in the amygdala, leading to damage to the cells in this brain structure. His neuropsychological examination revealed that his intelligence was within normal values, with preserved cognitive functions. However, his main deterioration was related to emotional information processing. He struggled to recognize fear in others and could not represent it through drawings despite his own lack of fear response.
The researchers attempted to induce fear in SM by exposing him to live snakes and spiders, taking him to a haunted hospital, and showing him horror films. However, SM showed no fear responses and instead displayed curiosity, fascination, and excitement in these situations. Despite his own lack of fear response, SM could acknowledge that most people would be scared by certain content in horror films.
Further studies following SM’s case have shown the importance of the amygdala in processing fear and other complex aspects such as attention and social cognition
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