What Can Neuroimaging Tell Us About Age-related Memory Changes?

Abstract

One of the most common and arguably most distressing such declines in aging, in large part because it is also an early sign of Alzheimer’s disease, is that of associative memory. Associative memory is the ability to bind and retrieve associations between items. These associations give long-term memories their episodic quality and allow us to distinguish one event from another. Healthy older adults report everyday difficulties in, for example, learning new names, and remembering the location of a placed item. Despite the prevalence of age-related associative memory complaints, the underlying neural mechanisms are poorly understood. In our lab, we use multiple methods including EEG and fMRI as well as neuropsychological assessment of brain injury patients to investigate this issue. Our work to date has shown that young and older adults engage similar cognitive processes and neural systems to support associative memory performance. However, age-related under-recruitment of the prefrontal cortex (PFC) and its associated operations is the most likely contributor to older adults’ impoverished associative memories. Our results have led us to postulate that the highest order PFC operations are disproportionately affected by age-related pathology and underlie much of the cognitive decline experienced in aging. Current research in the lab uses a multimodal approach to disentangle the contributions of PFC subregions to both encoding and retrieval to obtain a more complete understanding of the factors underlying age-related associative memory impairments.