Figure: Coupled hair cells (left): Fluorescence microscopy image of a cell cluster of five coupled inner hair cells (pear-shaped with bright spots).
The second cell from the left was loaded with a fluorescent dye that labels the synaptic ribbon using the patch-clamp technique. From there, the dye spreads into the neighbouring hair cells and marks the synaptic ribbons (bright spots). Source: Institute for Auditory Neuroscience / UMG.
A “mini-syncytium” of three coupled inner hair cells (right); the connection is simplified as a tube formed by fused cell membranes: The electrical signals are transmitted via coupling of the cells. This mechanism reduces the stochastic noise of signal transmission at the ribbon synapses with the neurons forming the auditory nerve. From there the information is transmitted to a common target neuron in the brain, further reducing the noise and resulting in higher hearing sensitivity.
Source: Jean et al., Nat Commun, 2020; Suppl. Part.

Coupled hair cells in the inner ear – „Together we are strong!“

When we hear, the sensory hair cells in the cochlea of the inner ear transduce sound signals of a certain pitch and convert them for transmission to the brain. For the first time, scientists of the Göttingen Campus, the Cluster of Excellence “Multiscale Bioimaging” and the University College London have shown that a third of the hair cells are connected with each other, presumably increasing the sensitivity of the sense of hearing to quiet sounds and the reliability of signal transmission. Published in Nature Communications.

Link to the press release