Age effects on hippocampal activation along the longitudinal axis in memory encoding task: An fMRI study
Date Issued
2010
Date
2010
Author(s)
Huang, Shuo-En
Abstract
Previous structural neuroimaging studies have found an anterior-posterior gradient of age-related volume reduction along the hippocampal longitudinal axis. However, there have been few functional neuroimaging studies that investigated this tendency in normal aging process. The current study applied functional MRI and ROI analysis to investigate the hippocampal activation during memory encoding tasks and the age-related changes along the hippocampal longitudinal axis in normal aging. 68 participants aged from 19 to 79 years old were recruited. The results showed a greater age-related functional reduction in the posterior hippocampus than the anterior hippocampus in the contrast that elicited posterior hippocampus primarily, while there was no significant effect of age on the behavioral performance. There was no significant age-related reduction in the contrast that elicited anterior hippocampus primarily, neither did age has a significant effect on the behavioral performance. This result was consistent with findings from previous structural neuroimaging studies. It was possible that the age-related functional reduction of the posterior hippocampus was compensated in other brain areas, while the behavioral performance was maintained at the same level. This anterior-posterior gradient of functional reduction might interfere with the memory association process, which was found to be possibly supported by the neural circuitry of the hippocampal longitudinal axis. This finding implicated an age-related functional reduction with the absence of decline in behavioral performance, and the normal aging process involved the posterior hippocampal functional reduction more than the anterior hippocampal functional reduction.
Subjects
hippocampus
longitudinal axis
fMRI
aging
memory encoding
Type
thesis
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