Successful Encoding within Retrieval: Neural Differences in Younger and Older Adults
Open Access
- Author:
- Ramasamy, Deepa
- Area of Honors:
- Biology
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Dr. Nancy Anne Coulter Dennis, Thesis Supervisor
Dr. Nancy Anne Coulter Dennis, Thesis Supervisor
Dr. James Harold Marden, Thesis Honors Advisor - Keywords:
- cognitive aging
incidental encoding
retrieval
PASA
HERA
memory - Abstract:
- The present study used a three part memory paradigm in order to test the neural activity of younger and older adults during a retrieval phase containing a simultaneous encoding phase. Specifically, age differences in neural activity associated with encoding success were examined while individuals performed a given retrieval task. Behavioral comparisons showed no significant differences in memory for younger and older adults. Neural activation results indicated common areas of successful encoding activation for younger and older adults in the ventrolateral prefrontal cortex, dorsolateral prefrontal cortex, parahippocampal gyrus (bilateral), anterior cingulate cortex, posterior cingulate and occiptal regions. The majority of activations were concentrated in the left hemisphere of the brain. A direct comparison between age groups indicated that younger adults activated more posterior regions than older adults, including regions in occipital/temporal, precuneus and posterior cingulate. Older adults activated more anterior regions, including the anterior cingulate cortex, dorsolateral prefrontal cortex and orbital frontal cortex. The results obtained indicate two main conclusions. The increased left lateralized activity seen in common for both younger and older adults is consistent with the hemispheric encoding/retrieval asymmetry (HERA) pattern, indicating that even though participants were taking part in both encoding and retrieval, brain regions predicting successful encoding were largely left-lateralized. Furthermore, results support the theory of a posterior-anterior shift in aging (PASA), indicating that as people age, anterior regions are used more often than posterior regions in order to store and retrieve information.