A Potential Mechanism of Brain Aging
Here, researchers investigate one of a number of mechanisms that may explain degeneration in the aging brain: "A common way of describing the behavior of older adults is that they are more rigid and set in their ways. The wide range in sensory and cognitive functional changes that accompany normal, healthy aging are suggestive of widespread cortical dysfunction. Neurobiological studies are beginning to link these functional changes and common descriptions with a loss of experience-dependent plasticity that reflects age-related changes in synaptic plasticity mechanisms. ... many changes occur at the aging synapse and it is likely that more than just one synaptic mechanism contributes to visual deficits in aging. Recent studies have highlighted the important role of ubiquitin-mediated degradation of proteins at the synapse as a potent mechanism for changing synaptic structure and function. ... Ube3A, an E3 ubiquitin ligase that is absent in Angelman's syndrome, is required for experience-dependent plasticity during development of the visual cortex. We found that Ube3A expression declines across the lifespan in human, monkey, and cat cortex. The losses were substantial (50–80%) in all areas studied."