Conditional spatial discrimination in humans with hypoxic brain injury

Hypoxic brain injury can cause severe anterograde amnesia with intact intel ligence and attention in select patients. This neuropsychological profile i s similar among a broad cla;ss of etiologies resulting in damage to the hip pocampus and associated medial temporal structures. Several recent studies have demonstrated that subjects with anterograde amnesia can nonetheless ac quire simple associative tasks. In the present study, the performance of su bjects with anterograde memory impairments resulting from hypoxic brain inj ury on a conditional spatial discrimination was examined. Quantitative magn etic resonance imaging revealed significant hippocampal atrophy in the hypo xic subjects. The hypoxic subjects were able to acquire and reverse the dis crimination, although they were slower relative to matched control subjects . Hypoxic subjects also showed a tendency to perseverate after reward conti ngencies were reversed.