S. m. is a patient who has been called "the woman with no fear", even of being threatened with a gun. her fearlessness is best attributed to damage to her:

Amygdala 

The amygdala is a part of the brain that is responsible for fear, threat perception and survival instincts. Damage to the amygdala therefore results in fearlessness since the brain is no longer properly able to identify threats and dangers. Thus, S.M.'s fearlessness despite being held at gunpoint can be attributed to amygdala damage.