SM was born in 1965 and from an early age 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.
The most striking thing about SM is that he did not recognize fear. Researchers conducted a study in 2010 to explore this further. They exposed SM to live snakes and spiders, took her on a tour of a haunted house, and showed her horror movies. When asked to draw fear, SM would draw a crawling baby. This research placed fear in the brain.
Patient 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. The main deterioration shown by the patient was related to emotional information processing.
SM had difficulty recognizing fear in others. While she could describe situations that could provoke fear and use different concepts to describe it, she struggled to represent this emotion through drawings. Despite her own lack of fear response, SM could acknowledge that most people would be scared by certain content in horror films.
The researchers attempted to induce fear in SM by exposing her to live snakes and spiders, taking her to a haunted hospital, and showing her horror films. However, SM showed no fear responses and instead displayed curiosity, fascination, and excitement in these situations.
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. Understanding how the brain processes fear through cases like SM’s could lead to treatments that prevent fear from dominating our lives.