We will be discussing sleep and dreaming in an upcoming lecture. I saw this video about an octopus observed during a rest period. The scientists were speculating about whether or not this represents dreaming.

In a current paper in Nature, researchers report that extended longevity in humans is associated with “downregulation of genes related to neural excitation and synaptic function, and upregulation of genes involved in immune function.” These findings build on prior work in the worm C. elegans showing that activity in a transcription factor aptly named REST affects neuronal excitation in aging. More REST leads to less neuronal excitation and longer lifespans. In this new research, investigators studied REST expression in elderly humans and found increased expression (and presumably less neuronal excitation) in elderly individuals greater than 85 years.

An article in the New York Times reported on a study published in Scientific Reports concerning white matter development in young adults. The study reported a strong correlation between memory and thinking skills with physical fitness. They also reported a correlation between fitness and white matter in the brain.

The study is observational and thus strong causal inferences cannot be drawn. A study that examines white matter changes in randomly drawn subject groups who are assigned to exercise and control groups would be much stronger. Nevertheless, there is good evidence from controlled studies in mice that exercise is good for the brain. Exercise in older adults can also slow the effects of aging on cognition.