The neural correlates mediating age deficits in novelty detection

Past research finds age-related increases in false recognitions, indicative of a general deficit in novelty detection. This deficit increases when novel items are semantically or perceptually related to items from study. However, little work has examined the neural mechanisms older adults (OAs) engage to avoid false recognitions and identify new information as novel. The present study scanned young adults (YAs) and OAs during a retrieval task in which new items were exemplars from studied categories (related novelty) or exemplars of unstudied categories (unrelated novelty) in order to detect age-related differences in the neural correlates mediating novelty detection of related and unrelated items. Results from related novelty detection indicated that YAs engaged a network of regions including bilateral visual, parietal, and prefrontal cortex more so than OAs. Instead, OAs showed increases only in left occipitoparietal cortex compared to YAs for related novelty detection. This suggests that OAs engage visuospatial attention to support related novelty detection but show a reduced sensory signal and less cognitive control, diminishing their ability to make subtle distinctions between related items. Regarding unrelated novelty detection, YAs showed engagement of lateral temporal regions and inferior parietal cortex while OAs showed increased activity in early visual regions and fusiform gyrus. These results suggest that while YAs can identify novel unrelated items based on categorical information alone, OAs engage sensory processing and object recognition. Therefore, age-related deficits in related novelty detection may be due to both deficits in cognitive control processes as well as a reduced specificity of sensory processing.