Lab
Lynn Nadel, Cognition and Neuroimaging Laboratory
Lab Website
http://web.arizona.edu/~cnl/
Rotation Labs
Lynn Nadel, Bruce McNaughton
Minor
Psychology
Research Summary
Multiple trace theory (MTT) predicts that hippocampal memory traces expand and strengthen as a function of repeated memory retrievals. We tested this hypothesis utilizing fMRI, comparing the effect of memory retrieval versus the mere passage of time on hippocampal activation. While undergoing fMRI scanning, participants retrieved remote autobiographical memories that had been previously retrieved either one month earlier, two days earlier, or multiple times during the preceding month. Behavioral analyses revealed that the number and consistency of memory details retrieved increased with multiple retrievals but not with the passage of time. While all three retrieval conditions activated a similar set of brain regions normally associated with autobiographical memory retrieval including medial temporal lobe structures, hippocampal activation did not change as a function of either multiple retrievals or the passage of time. However, activation in other brain regions, including the precuneus, lateral prefrontal cortex, parietal cortex, lateral temporal lobe, and perirhinal cortex increased after multiple retrievals, but were not influenced by the passage of time. These results have important implications for existing theories of long-term memory consolidation.
I am mainly interested in mechanisms of human learning and memory, specifically processes of memory consolidation and human autobiographical and spatial memory, and utilizing functional magnetic resonance imaging (fMRI) as a method to explore these processes in healthy human populations. Generally, my interests are focused on the areas of the brain involved in memory systems, specifically the hippocampus not only for its known role in human episodic memory but also other cognitive processes such as spatial and relational learning. Through understanding more thoroughly aspects regarding the mechanisms by which normal memory systems operate, by virtue we will gain an understanding of the ways in which those systems can become impaired, especially with regards to human pathologies such as Alzheimer’s disease, currently afflicting 5% of individuals over the age of 65 and 50% of individuals over the age of 85. As a technique, fMRI provides a non-invasive method of localizing brain activity temporally and spatially, providing insights into mechanisms that have never before been addressed in the human brain and that have previously solely been examined using animal models and human behavioral testing. The possibilities of the areas to be explored and the research questions that await asking are seemingly endless. The prospect of being involved in this forthcoming movement of research is very exciting and motivating.
Recent Publications
Nadel, L., Campbell, J.L., & Ryan, L. (2007). Autobiographical memory retrieval and
hippocampal activation as a function of repetition and the passage of time. Neural Plasticity, 2007: 1-14.
Campbell, J.L., Nadel, L., Duke, D.S., & Ryan, L. (submitted). Remembering All That
and Then Some: Recollection of Autobiographical Memories after a One-Year Delay. Psychological Science. |
