Diminished ability to interpret and report internal states after bilateral medial temporal resection: case H.M.

These experiments centered around H.M., a 54-year-old man who became amnesic 27 years ago after a bilateral resection in the medial temporal lobe region for epilepsy. In order to document the clinical reports that he rarely comments on such internal states as pain, hunger, and thirst, his thermal pain perception was examined in relation to his other somatosensory capacities, and his reports of hunger and thirst were assessed before and after meals. In order to investigate the effect of limited memory ability on the reporting of internal states, H.M.'s performance was compared with that of 5 other subjects with global amnesia. The results provided evidence that H.M.'s information about internal states is less available or less accessible than normal and that his impairment is not attributable to his well-documented memory deficit. Instead, it is believed that the bilateral resection of the amygdala accounts for H.M.'s poor appreciation of his internal states.