Interactions of attention and memory in aging and mild cognitive impairment
Waring, Jill D. “Interactions of attention and memory in aging and mild cognitive impairment”. PhD, Boston College, 2011. http://hdl.handle.net/2345/3737.
Although healthy young and older adults remember emotional information better than neutral, emotion does not confer the same benefit upon memory for those experiencing memory impairments due to Alzheimer's disease (AD). It is poorly understood at what stage of processing these deficits occur--are they due to declines in memory storage and retrieval processes, or to a decline in earlier stages of attention allocation, which then impact memory storage and retrieval? It remains an open question how attention and memory processes may interact in aging and age-related disease. The goal of this research was to examine the effects of aging on the neural mechanisms underlying selective memory for emotional information in visual scenes, and to compare memory between healthy older adults and patients with very early AD pathophysiological changes. Experiment 1 examined young and older adults' encoding-related neural activation associated with selective memory for emotional items within visual scenes and with successful memory for emotional items and the scene background. There were few regions showing significant interactions between age and memory for positive and negative scenes. In contrast, Experiment 2 showed that aging significantly affected the neural networks underlying selective emotional item memory and successful memory for emotional items and backgrounds. The results indicate that older adults require greater connectivity among prefrontal regions than young adults to encode all elements of a scene, rather than just encoding the emotional item. Experiment 3 showed that despite poorer memory overall, patients showing very early AD pathophysiological changes have relatively well preserved memory, especially for positive information. Dividing older adults' attention during encoding did not significantly alter their pattern of selective emotional item memory, suggesting that encoding of emotional items may be an easier or relatively automatic task compared to encoding of the background. In conclusion, there are significant age-related changes in the underlying neural networks, but not activation patterns, for selective memory for positive and negative scenes. Patients with early AD pathophysiological changes have impaired memory overall, however they may be able to recruit a similar neural network of prefrontal regions as healthy older adults for encoding of scenes with positive information.