Memory function declines in normal and pathological brain aging. A significant research effort pursues methods to slow or stop this process. The brain mechanism underlying age-related memory decline is poorly understood. Limited evidence exists for specific types of cognitive exercise to change brain structure and function. A recent study of a small number of elderly individuals provides support for the potential of memory exercise to change brain structure.
Engvid and colleagues at the University of Oslo in Norway recently published a study of intense memory exercise and brain white matter using an imaging technique called diffusion tensor imaging in the journal Human Brain Mapping. Diffusion tensor imaging or DTI is a recently emerging technique that provides information about the structure and function of the brain's white matter. White matter is the key network connection part of the brain that connects different brain regions providing pathways for communication and complex brain functioning.
The figure to the right is a model of a human brain white matter imaged through the use of DTI. Along with outlining the anatomy of white matter, DTI provides an estimate of connectivity through measuring the flow of water molecules in white matter.
In the Engvid study, the experimental group completed an eight week memory improvement training course using the Method of Loci. I had not been familiar with this intervention. Essentially it involves serially imaging a series of points in the home with retrieval of information about each point or loci. The second reference contains more detailed information about this memory exercise technique.
The experimental group completed this exercise of 25 minutes one time per week in the lab and then was instructed to complete the exercise at home four days per week with completion of homework assignments. The average age of the study groups was about 60 years to assess this training effect in a group with significant aging effects.
The subjects were scanned using DTI at baseline and following eight weeks of memory training. A control group was scanned at baseline and at week 8 and were instructed to maintain their typical lifestyle during the period. The results of the study were pretty impressive and including the following key findings:
- White matter mean diffusivity increased in the frontal regions of the memory exercise group
- A measure of white matter function called functional anisotropy (FA) increased in the memory exercise group
- The level of FA change correlated with the level of improvement in a neuropsychological test of memory
You will likely see more research examining change in memory and other cognitive functions with cognitive exercises. Using sensitive imaging techniques holds the promise of honing in on the best brain exercises to limited the effects of aging on the brain.
Photo of Juno Beach sunrise using a thermal image filter from the author's collection. Original photo can be found here.
Image of brain white matter using DTI from the Wikipedia Commons file authored by Thomas Schultz. The author's description of the image:
"Visualization of a DTI measurement of a human brain. Depicted are reconstructed fiber tracts that run through the mid-sagittal plane. Especially prominent are the U-shaped fibers that connect the two hemispheres through the corpus callosum (the fibers come out of the image plane and consequently bend towards the top) and the fiber tracts that descend toward the spine (blue, within the image plane)"
Engvig, A., Fjell, A., Westlye, L., Moberget, T., Sundseth, �., Larsen, V., & Walhovd, K. (2010). Effects of memory training on cortical thickness in the elderly NeuroImage, 52 (4), 1667-1676 DOI: 10.1016/j.neuroimage.2010.05.041
No comments:
Post a Comment