The belief that healthy older brains are substantially smaller than younger brains may stem from studies that did not screen out people whose undetected, slowly developing brain disease was killing off cells in key areas, according to new research. As a result, previous findings may have overestimated atrophy and underestimated normal size for the older brain.

The healthy brain is in a constant struggle between learning new experiences and remembering old experiences, a new study in this week's PLoS Biology reports.

Canadian scientists have shown that a noisy brain is a healthy brain.

Treatments to keep the brain healthy can be just as effective as exercise is for the body, according to the latest special issue of The Journal of Gerontology: Psychological Sciences. The volume, titled "Cognitive Interventions and Aging," features research devoted to methods for preserving mental function - from training routines and medication to more modern approaches such as civic engagement and the use of technology.

Yes, there are gender differences in cognitive function, but they're more limited than previously thought. And yes, income does affect cognitive performance - but less than expected when only healthy children are considered. And while basic cognitive skills steadily improve in middle childhood, they then seem to level off - questioning the idea of a burst of brain development in adolescence.