Brain Volume Differences and Proactive Interference: A VBM Investigation of Healthy Cognitive Aging.

Research on aging and memory has consistently demonstrated decreased memory performance in older adults, specifically on tasks measuring verbal and spatial memory. Memory decline in aging is partially related to interference from competing information. In older adults, the learning of new information is more adversely affected by already-formed memories (i.e. proactive interference) than in younger adults. However, interference of new information on already- formed memories (retroactive interference) is less affected by age. The present investigation examined the association between proactive and retroactive interference, and brain volume in young and older adults. Proactive and retroactive interference were assessed with a Modified modified free recall (MMFR) test. Participants (n=39) first studied AB and DE word pairs three times before undergoing a cued recall test. Following AB-DE testing, participants had only one study-test cycle of AC and FG word pairs. Finally, participants completed the MMFR test to evaluate their memory for all previously studied and tested words. Results revealed that older adults experienced significantly more proactive interference than younger adults (performance on MMFR-AC minus MMFR-FG), but both age groups performed similarly on the retroactive interference measures. It was hypothesized that brain volume, and specifically Hippocampal and prefrontal volume, would be significantly correlated to memory performance; however no significant correlations were found with any specific brain regions