The Brain Signal (IMAGE) Trinity College Dublin Caption When a listener understands speech, a strong response signal is seen over the mid back part of their scalp (top row; blue and green waveforms show response at two specific recording locations). When they can't understand (because, for example, the speech is played backwards), the signal completely disappears (bottom row; red and yellow waveforms show the lack of response at the same two specific recording locations). Credit Professor Ed Lalor. Usage Restrictions Please credit Professor Ed Lalor. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.