(Medical Xpress)—When the brains of those who have succumbed to age-related neurodegeneration are analyzed post-mortem, they typically show significant atrophy on all scales
Not only is the cortex thinner and sparser, but the hollow ventricles inside the brain are grossly enlarged. In the absence of any specific disease, these general trends are still familiar. It has traditionally been assumed that the dynamic microfeatures of aged brains—the growth of the fine neurites and the synapses they make—would similarly be degenerate. In other words, synaptic growth would have either entered some form of stasis, or alternatively, a state of permanent decay with replacement by matrix or scar tissue. Contrary to these expectations, recent research shows increased structural plasticity in the axonal component of synapses in the aged mouse cortex. Reporting in the current issues of PNAS, researchers provide evidence that the observed behavioral deficits in these animals may be due to an inability to maintain persistent synaptic structure, rather than because of a loss of plasticity.
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