The perirhinal cortex and recognition memory interference.

There has recently been an increase in interest in the effects of visual interference on memory processing, with the aim of elucidating the role of the perirhinal cortex (PRC) in recognition memory. One view argues that the PRC processes highly complex conjunctions of object features, and recent evidence from rodents suggests that these representations may be vital for buffering against the effects of pre-retrieval interference on object recognition memory. To investigate whether PRC-dependent object representations play a similar role in humans, we used functional magnetic resonance imaging to scan neurologically healthy participants while they performed a novel interference-match-to-sample task. This paradigm was specifically designed to concurrently assess the impact of object versus spatial interference, on recognition memory for objects or scenes, while keeping constant the amount of object and scene information presented across all trials. Activity at retrieval was examined, within an anatomically defined PRC region of interest, according to the demand for object or scene memory, following a period of object compared with spatial interference. Critically, we found greater PRC activity for object memory following object interference, compared with object memory following scene interference, and no difference between object and scene interference for scene recognition. These data demonstrate a role for the human PRC during object recognition memory, following a period of object, but not scene interference, and emphasize the importance of representational content to mnemonic processing.