The hippocampus of the brain is important for memory and orientation. Because of its role in memory, and because it is one of the main areas of the brain that Alzheimer’s Disease and certain other neurological disorders cause damage to, it is a major area of focus for scientific research on the cognitive effects of aging. A team of German researchers have found a gene in mice that is associated with a decline in the production of new neurons in the hippocampus. Neuron production is thought to be important for the brain’s ability to retain new memories. It is hoped that future research will determine whether this finding applies to humans as well, which may make it possible to develop new drugs that block this gene.
The proteins created by the gene, called Dickkopf-1 or Dkk1 (German for “thick head”), have been found in greater proportion in older mice than in younger mice. Researchers suspected that this may be why the hippocampi of older mice generate fewer new neurons. To test this, the researchers bred mice to lack the expression of Dkk1 in the brain, and compared the brain and the spatial orientation skills of the Dkk1-blocked mice with a control group of mice. The researchers found that Dkk1-blocked mice continued to generate new neurons at a significantly greater rate than the control mice, and experienced no decline in spatial ability.
Although animal model studies like this one often fail to be replicated in humans, the hippocampus is very similar in structure and, it appears, function across mammals. Studies in mice and rats have made significant contributions to scientific understandings of the human hippocampus, and while it remains to be seen if Dkk1 plays a similar role in both mice and humans, this would be a promising finding for research on memory and cognitive decline.
Sieb DRM, Corsini NS, Ellwanger K, et al. Loss of Dickkopf-1 restores neurogenesis in old age and counteracts cognitive decline. Cell Stem Cell (2013). 12(2) 204-14.