Berkeley, CA, USA. Neuroscientists can explain how fear stimulates new memories. The amygdala, the brain's emotional center, induces the hippocampus, a relay hub for memory, to generate new neurons.

In a fearful situation, these newborn neurons get activated by the amygdala and may provide a blank slate to strongly imprint the new fearful memory. In evolutionary terms, it means new neurons are likely helping you to remember the lion that nearly killed you.

University Park, PA, USA. Scientists have used large-scale DNA sequencing data to investigate a basic and long-standing evolutionary assumption: DNA mutation rates are influenced by a set of species-specific life-history traits.

These traits include metabolic rate and the interval of time between an individual's birth and the birth of its offspring, known as generation time, and the struggle between the sperm of different males to fertilize egg cells.