Visual hallucinations of autobiographical memories: a single-case study.

Introduction: We report an epileptic patient who experienced hallucinatory visual experiences of autobiographical memories from her past. These visual experiences were confined to the lower left quadrant of her visual field. Methods: We carried out a single-case study that used brain-imaging, EEG and behavioural methods to study this patient. Results: We found that this patient had an incomplete left inferior homonymous quadrantanopia due to a lesion of right occipital cortex, and also that she showed neurological abnormalities in right temporal cortex, a region that is part of the brain's autobiographical-memory circuit. Conclusion: We attribute the occurrence of this patient's autobiographical-memory hallucinations to the combination of degraded visual input to right temporal cortex plus hyperexcitability of that region.