In California, scientists have developed a mathematical model that matches brain patterns with images. Science correspondent James Randerson says it could be an important step towards a machine that can read your mind – or at least, reproduce an image pictured in the brain.
Hillary Clinton's comeback in Tuesday's primary elections in Ohio and Texas puts her back in the race for the Democratic presidential nomination. But John McCain is now confirmed as the man the Republicans want to return them to the White House, giving him a clear advantage over the warring Democrats, says columnist Jonathan Freedland.
Ken Livingstone's hopes of being re-elected for a third term as London mayor in May suffered a blow this week with the resignation of his race advisor Lee Jasper. Hugh Muir outlines the allegations facing Mr Jasper and the mayor and explains how they will affect Mr Livingstone's campaign.
Ian Paisley's decision to step down as Northern Ireland first minister and leader of the Democratic Unionists is explained by Ireland correspondent Henry McDonald. His expected successor, Peter Robinson, is expected to be rather less chummy with the deputy first minister, Sinn Féin's Martin McGuinness.
And Kate Connolly reports from Berlin, where forensic scientists have attempted to recreate what they say is the "true face" of composer Johann Sebastian Bach.
