Scientists Hack Zebrafish Earbones With Light to Control Heart Rhythms

Scientists control zebrafish heart rates by manipulating their earbones with optical tweezers. Researchers used optical tweezers to move tiny calcium carbonate crystals that the sensory system responds to. The targeted optical stimulation increased resting heart rates from 2 beats per second to about 2.7. In subjects with drug-induced arrhythmias, normal chamber coordination returned in six of seven animals. "The fact that a purely optical stimulus, delivered through the auditory pathway, could restore normal cardiac rhythm in a disease model exceeded our initial expectations and might open up exciting possibilities for future therapeutic applications." — Xiaoshuai Liu Bypassing the heart to fix arrhythmias through the ear proves biological circuitry operates on a physical logic that doesn't match our current medical hardware.