Study tests exercise, BDNF and cognition

The Guardian’s science editor, Ian Sample, talks to Madeleine Finlay about three eye-catching science stories from the week, including a study that explores the link between exercise and brain health. Also on the agenda: the discovery that hedgehogs can hear high-frequency ultrasound and what this could mean for their conservation, and new research examining how biased AI autocomplete tools can influence the beliefs of users.. Help support our independent journalism at theguardian.com/sciencepod