Hair Bundle (IMAGE) Boston Children's Hospital Caption Three mechanosensory hair bundles from the cochlea. When sound vibrations strike the bundle, the hairs, or microvilli, wiggle back and forth, opening and closing channels formed by TMC proteins. When open, the channels allow calcium into the cell, initiating electrical signals that travel to the brain. Credit (Image: Gwenaelle S. Geleoc & Artur A. Indzhykulian) Usage Restrictions None 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.