Small prints:As we get older, it's common to experience changes in sleep patterns. Meanwhile, in older age, a part of the brain called the prefrontal cortex tends to shrink.
Could these events be linked to poorer memory?
Research in the US suggests that a disruption in “slow-wave” sleep in older adults is linked with less-effective processing of memories.
The study, which is published in Nature Neuroscience, measured the effects of sleep on memory retention in 18 young adults (mostly 20-somethings) and in 15 older adults (mostly 70-somethings).
The study also analysed their brain activity during sleep and looked at brain structure.
The results indicate that a deterioration of the prefrontal cortex in older people was linked to reduced slow-wave sleep, and also a reduced ability to retain learned information after sleep.
“When we are young, we have deep sleep that helps the brain store and retain new facts and information,” says study author Matthew Walker from the University of California, Berkeley, in a statement.
“But as we get older, the quality of our sleep deteriorates and prevents those memories from being saved by the brain at night.”
Shane O’Mara, professor of experimental brain research at Trinity College Dublin, who was not involved in the study, commends the research.
“Locating changes in particular brain regions, tying them to cognitive function, or memory, and giving the neurophysiology to bring them together is a really neat piece of work,” he says.
“Sleep is vital for normal memory function, and other research suggests that regular aerobic exercise may improve sleep quality and assist memory function.”
The first insects to look to the stars? Scarab beetles
They may be involved in the glamorous job of rolling dung but, according to new research, scarab beetles are looking to the stars when trying to figure out where to roll it at night.
When it gets some dung, a male beetle fashions the precious find into a ball and it’s thought the insect will roll it in a straight line to get away from the competition of rivals.
So what happens at night? The researchers set up experiments to find out. They tracked scarab beetles (Scarabaeus satyrus) in South Africa as they rolled dung in an enclosed circular arena.
On moonless nights when stars were visible, many of the beetles could still orientate along a straight path.
But if it was overcast, or if their view of the night sky was blocked by little cardboard caps, the ability to keep a straight line was reduced, the authors report in Current Biology.
Next they moved the arena into Johannesburg Planetarium and tracked how the beetles moved under various representations of the starry sky.
Their findings suggest that “the beetles do not orientate to a single bright ‘lodestar’, but rather to the band of light that represents the Milky Way,” according to the study authors.
“This finding represents the first convincing demonstration for the use of the starry sky for orientation in insects and provides the first documented use of the Milky Way for orientation in the animal kingdom.”
