1 Centre for Developmental Cognitive Neuroscience, UCL Great Ormond Street Institute of Child Health, London, UK; Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK. Electronic address: f.vargha-khadem@ucl.ac.uk.
2 Centre for Developmental Cognitive Neuroscience, UCL Great Ormond Street Institute of Child Health, London, UK; Dept. of Neuroscience, Physiology and Pharmacology, UCL, London, UK.